稀土镁合金变壁厚异型板类构件控形控性研究
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摘要
镁合金变壁厚异型板类构件是弹箭装备的轻量化部件,其力学性能与尺寸精度直接关系到装备可靠性与打击精度。添加稀土元素的镁合金较常规镁合金具有更好的高温性能,但是这些耐热镁合金铸造产品成分偏析和夹杂严重,力学性能低,难以满足高速飞行弹箭装备的需求。塑性成形可大幅提高镁合金构件的力学性能,但镁合金为密排六方晶体结构,塑性较差。含稀土镁合金成形更易开裂,成形构件各向异性更加明显。
国内研制的新型高强耐热Mg-13Gd-4Y-2Zn-0.6Zr合金,在航空航天、国防军工具有很好的应用前景,目前关于此合金的塑性变形特性研究较少。变壁厚异型板类构件通常采用稀土镁合金铸锭多向锻造开坯、通过多方向上大塑性变形实现细晶强化,这是改善成形构件各向异性与获得良好力学性能的重要手段；Mg-13Gd-4Y-2Zn-0.6Zr合金多向锻造过程中的塑性变形历史与组织响应规律,目前也没有研究涉及。变壁厚异型板类构件由于其苛刻的服役条件,力学性能与尺寸精度要求严格,必须采用控形控性一体化的塑性成形方法,实现筋条处金属充填、变形均匀性以及成形过程微观组织结构演变的协调控制,这也是当下研究的热点问题。
针对Mg-13Gd-4Y-2Zn-0.6Zr合金,借助于热模拟压缩实验、光学金相显微分析、扫描电镜和能谱分析、硬度测试、室温／高温拉伸实验等研究手段,系统研究了不同变形参数下合金的流变行为,以及随着变形道次的变化合金内部显微组织的演化规律,为该类合金的塑性变形提供了实验依据。热模拟压缩试验表明：应变速率介于0.001～0.5s-1以及变形温度介于573-753K时,其真应力-真应变曲线都呈现动态再结晶特征。在合金热塑性变形过程中,动态硬化和动态软化的竞争贯穿始终；随着变形温度的升高,组织内部的动态回复和动态再结晶加剧,表现为流变应力的降低。基于Sellars方程,构建了Mg-13Gd-4Y-2Zn-0.6Zr合金不同应力状态的本构模型。基于动态材料模型建立了合金二维热加工图,发现Mg-13Gd-4Y-2Zn-0.6Zr合金具有两个峰值能量耗散区域：1)温度680～740K、应变速率0.001-0.01s-1；2)温度730-753K,应变速率0.01-0.1s-1；两区域能量耗散效率分别在30～40%和40～49%之间,这为成形工艺参数的选择提供了参考依据。
研究了Mg-13Gd-4Y-2Zn-0.6Zr合金多道次变形特征。研究结果表明：随着变形道次的增加,变形过程中的动态软化程度减小,而道次间的静态软化程度持续增强。但由于变形过程中的加工硬化远远大于综合软化的效果,表现为真应力-真应变曲线的峰值流变应力快速上升。单道次变形相比,两道次相对软化了9.42%、三道次相对软化了33.07%、四道次相对软化了24.5%。可以看出,三道次变形相对软化程度最大,四道次后由于动态硬化程度加剧,软化程度降低。
从塑性应变、晶粒尺寸、成形损伤的角度,研究了稀土镁合金变壁厚异型板类构件塑性成形的控性问题：从金属充填饱满时成形载荷的角度,研究了构件成形控形的问题。提出将洛伦兹曲线与基尼系数应用于评估构件变形均匀性；从应变、晶粒尺寸、损伤因子这三方面来考虑,提出了三个变形均匀性评价因子。以三个变形均匀性评价因子和成形载荷为多目标优化问题的目标函数,以两个分流孔的直径、挤压成形用坯料厚度、成形温度与成形速度为设计变量,通过正交试验设计、有限元模拟、灰色关联系数计算、基于层次分析法实现目标函数权重分配、灰色关联度计算,依据关联度大小获得了多目标优化的成形工艺参数组合。
在优化的参数组合基础上,设计了各工序的控制成形模具,进行稀土镁合金变壁厚异型板类的多道次预变形及最终成形的工艺设计和实验验证,试制出了符合性能与尺寸要求的品质均匀的构件,通过了考核实验,为扩大稀土镁合金的应用提供了有力的技术支撑。
The special-typed panel component produced by magnesium-based alloys containing rare-earth (RE) metals with variable wall thickness is one of the important lightweight parts of projectiles and rockets. Its mechanical properties and dimensional precision have a direct influence on projectiles and rockets'reliability and target accuracy. RE-Magnesium-based alloys have better high-temperature resistance than the common magnesium alloys. However, the cast products by magnesium-based alloys containing rare-earth metals cannot satisfy the demands of high-speed flying projectiles and rockets, due to their low mechanical performances caused by composition segregation and inclusion defects. Although plastic forming could be an efficien way to improve the mechanical properties of magnesium alloy components, magnesium alloy has low plasticity because of its hexagonal close-packed structure. However, magnesium alloy added with RE metals is even more easily to crack during plastic forming, and the forming components have more obvious anisotropic character.
Mg-13Gd-4Y-2Zn-0.6Zr alloy has good properties for its high strength and heat resistance. This makes it particularly attractive for aerospace, national defense and military and other fields. However, there are few studies on the alloy's plastic forming. The panel component with variable wall thickness is usually cogged for cast ingot by multiple forging. The fine grain strengthening can be obtained by the severe plastic deformation in varying directions, which is the important method to improve the component's anisotropy and acquire high mechanical performance. Moreover, at present, no studies involve microstructure response law about the plastic deformation history during the multiple forging for Mg-13Gd-4Y-2Zn-0.6Zr alloy. The mechanical performance and dimensional precision of the panel component with variable wall thickness are strictly required, owing to the alloy's tough serving condition. The method of shape-and-performance controllability integration is applied to realize the coordinated control of metal filling in the rib, forming uniformity and the microstructure evolution, which are also the research focus in this field.
Mg-13Gd-4Y-2Zn-0.6Zr alloy was analyzed in this paper by means of isothermal compression, optical microscopy, scanning electron microscopy, energy spectrum, hardness testing, tensile test at room temperature and high temperature etc. The deformation behavior of the alloy with different deformation parameters is systematically studied, as well as the microstructure evolution law in the alloy during the deformation passes, which provides the experimental basis for the plastic deformation of the alloy. The isothermal compression test of Mg-13Gd-4Y-2Zn-0.6Zr alloy shows that, when the strain rate is0.001～0.5s-1and deformation temperature is573-753K, true stress-true strain curve has the character of dynamic recrystallization. During the process of thermo-plastic deformation, the competition between the dynamic hardening and softening run all along. With the deformation temperature rising, true stress-true strain curve show the character of low flow stress because the dynamic recovery and dynamic recrystallization increase.Based on the equation of Sellars, the constitutive model of the alloy under the different stress states was established. And based on the dynamic material model, the alloy's two-dimension processing map was created, which showed that the alloy has two peak energy dissipation areas:1) when the temperature range is680-740K and strain rate range is0.001-0.01s-1,2) when the temperature range is730-753K and strain rate range is0.01-0.1s-1. The energy dissipation efficiencies are about30-40%and40～49%, respectively. This provides the reference for choosing the forming parameters.
The multiple passes forming features of Mg-13Gd-4Y-2Zn-0.6Zr was analyzed in this paper.The results show that dynamic softening decreases when the passes increase, while static softening strengthens continuously. However, the work hardening during the deformation process is far beyond the combined softening, as shown as the peak flow stress rises rapidly in true stress-true strain curve. Compared with the single pass deformation, relative softening degree is9.42%after two passes,33.07%after three passes and24.5%after four passes. It can be investigated that the relative softening degree is the maximum after three passes. The reason for the fall of softening degree after four passes is that the dynamic hardening increases at the same time.
The performance controllability of the panel component produced by rare-earth metals added into magnesium-based alloy with variable wall thickness was studied from the prospectives of plastic strains, grain sizes and forming damage, while the shape controllability of the component was analyzed by the means of forming load when the metal filling reaches full. This paper applies the Lorentz curve and Geordie Coefficient into the deformation uniformity of the forming component. Three aspects including straining, grain size, and damage factor are considered as evaluation factors of the deformation uniformity for the forming component. The objective function of multi-objective optimization problem with three forming uniformity evaluation factors and forming load is established based on the diameters of two Diversion holes, blank thickness for extrusion, forming temperature and speed as variables. By means of orthogonal test, finite element modeling, grey incidence coefficient calculation and AHP (analytical hierarchy process), the weight distribution and grey correlation degrees of the objective function can be realized. And the forming parameters combination from multi-objective optimization can be obtained according to the numerical value of correlation degree.
Finally, on the basis of the optimized parameters combination, the forming controlling dies were designed, and the multiple passes pre-deformation and final forming technology of the panel component produced by rare-earth metals added into magnesium alloy with variable wall thickness were fabricated, and then the technology was validated. The forming component with even properties meets the properties and dimensional requirements in the design, which is a strong technical support for the wider applications of magnesium alloys added with rare-earth metals.
国内研制的新型高强耐热Mg-13Gd-4Y-2Zn-0.6Zr合金,在航空航天、国防军工具有很好的应用前景,目前关于此合金的塑性变形特性研究较少。变壁厚异型板类构件通常采用稀土镁合金铸锭多向锻造开坯、通过多方向上大塑性变形实现细晶强化,这是改善成形构件各向异性与获得良好力学性能的重要手段；Mg-13Gd-4Y-2Zn-0.6Zr合金多向锻造过程中的塑性变形历史与组织响应规律,目前也没有研究涉及。变壁厚异型板类构件由于其苛刻的服役条件,力学性能与尺寸精度要求严格,必须采用控形控性一体化的塑性成形方法,实现筋条处金属充填、变形均匀性以及成形过程微观组织结构演变的协调控制,这也是当下研究的热点问题。
针对Mg-13Gd-4Y-2Zn-0.6Zr合金,借助于热模拟压缩实验、光学金相显微分析、扫描电镜和能谱分析、硬度测试、室温／高温拉伸实验等研究手段,系统研究了不同变形参数下合金的流变行为,以及随着变形道次的变化合金内部显微组织的演化规律,为该类合金的塑性变形提供了实验依据。热模拟压缩试验表明：应变速率介于0.001～0.5s-1以及变形温度介于573-753K时,其真应力-真应变曲线都呈现动态再结晶特征。在合金热塑性变形过程中,动态硬化和动态软化的竞争贯穿始终；随着变形温度的升高,组织内部的动态回复和动态再结晶加剧,表现为流变应力的降低。基于Sellars方程,构建了Mg-13Gd-4Y-2Zn-0.6Zr合金不同应力状态的本构模型。基于动态材料模型建立了合金二维热加工图,发现Mg-13Gd-4Y-2Zn-0.6Zr合金具有两个峰值能量耗散区域：1)温度680～740K、应变速率0.001-0.01s-1；2)温度730-753K,应变速率0.01-0.1s-1；两区域能量耗散效率分别在30～40%和40～49%之间,这为成形工艺参数的选择提供了参考依据。
研究了Mg-13Gd-4Y-2Zn-0.6Zr合金多道次变形特征。研究结果表明：随着变形道次的增加,变形过程中的动态软化程度减小,而道次间的静态软化程度持续增强。但由于变形过程中的加工硬化远远大于综合软化的效果,表现为真应力-真应变曲线的峰值流变应力快速上升。单道次变形相比,两道次相对软化了9.42%、三道次相对软化了33.07%、四道次相对软化了24.5%。可以看出,三道次变形相对软化程度最大,四道次后由于动态硬化程度加剧,软化程度降低。
从塑性应变、晶粒尺寸、成形损伤的角度,研究了稀土镁合金变壁厚异型板类构件塑性成形的控性问题：从金属充填饱满时成形载荷的角度,研究了构件成形控形的问题。提出将洛伦兹曲线与基尼系数应用于评估构件变形均匀性；从应变、晶粒尺寸、损伤因子这三方面来考虑,提出了三个变形均匀性评价因子。以三个变形均匀性评价因子和成形载荷为多目标优化问题的目标函数,以两个分流孔的直径、挤压成形用坯料厚度、成形温度与成形速度为设计变量,通过正交试验设计、有限元模拟、灰色关联系数计算、基于层次分析法实现目标函数权重分配、灰色关联度计算,依据关联度大小获得了多目标优化的成形工艺参数组合。
在优化的参数组合基础上,设计了各工序的控制成形模具,进行稀土镁合金变壁厚异型板类的多道次预变形及最终成形的工艺设计和实验验证,试制出了符合性能与尺寸要求的品质均匀的构件,通过了考核实验,为扩大稀土镁合金的应用提供了有力的技术支撑。
The special-typed panel component produced by magnesium-based alloys containing rare-earth (RE) metals with variable wall thickness is one of the important lightweight parts of projectiles and rockets. Its mechanical properties and dimensional precision have a direct influence on projectiles and rockets'reliability and target accuracy. RE-Magnesium-based alloys have better high-temperature resistance than the common magnesium alloys. However, the cast products by magnesium-based alloys containing rare-earth metals cannot satisfy the demands of high-speed flying projectiles and rockets, due to their low mechanical performances caused by composition segregation and inclusion defects. Although plastic forming could be an efficien way to improve the mechanical properties of magnesium alloy components, magnesium alloy has low plasticity because of its hexagonal close-packed structure. However, magnesium alloy added with RE metals is even more easily to crack during plastic forming, and the forming components have more obvious anisotropic character.
Mg-13Gd-4Y-2Zn-0.6Zr alloy has good properties for its high strength and heat resistance. This makes it particularly attractive for aerospace, national defense and military and other fields. However, there are few studies on the alloy's plastic forming. The panel component with variable wall thickness is usually cogged for cast ingot by multiple forging. The fine grain strengthening can be obtained by the severe plastic deformation in varying directions, which is the important method to improve the component's anisotropy and acquire high mechanical performance. Moreover, at present, no studies involve microstructure response law about the plastic deformation history during the multiple forging for Mg-13Gd-4Y-2Zn-0.6Zr alloy. The mechanical performance and dimensional precision of the panel component with variable wall thickness are strictly required, owing to the alloy's tough serving condition. The method of shape-and-performance controllability integration is applied to realize the coordinated control of metal filling in the rib, forming uniformity and the microstructure evolution, which are also the research focus in this field.
Mg-13Gd-4Y-2Zn-0.6Zr alloy was analyzed in this paper by means of isothermal compression, optical microscopy, scanning electron microscopy, energy spectrum, hardness testing, tensile test at room temperature and high temperature etc. The deformation behavior of the alloy with different deformation parameters is systematically studied, as well as the microstructure evolution law in the alloy during the deformation passes, which provides the experimental basis for the plastic deformation of the alloy. The isothermal compression test of Mg-13Gd-4Y-2Zn-0.6Zr alloy shows that, when the strain rate is0.001～0.5s-1and deformation temperature is573-753K, true stress-true strain curve has the character of dynamic recrystallization. During the process of thermo-plastic deformation, the competition between the dynamic hardening and softening run all along. With the deformation temperature rising, true stress-true strain curve show the character of low flow stress because the dynamic recovery and dynamic recrystallization increase.Based on the equation of Sellars, the constitutive model of the alloy under the different stress states was established. And based on the dynamic material model, the alloy's two-dimension processing map was created, which showed that the alloy has two peak energy dissipation areas:1) when the temperature range is680-740K and strain rate range is0.001-0.01s-1,2) when the temperature range is730-753K and strain rate range is0.01-0.1s-1. The energy dissipation efficiencies are about30-40%and40～49%, respectively. This provides the reference for choosing the forming parameters.
The multiple passes forming features of Mg-13Gd-4Y-2Zn-0.6Zr was analyzed in this paper.The results show that dynamic softening decreases when the passes increase, while static softening strengthens continuously. However, the work hardening during the deformation process is far beyond the combined softening, as shown as the peak flow stress rises rapidly in true stress-true strain curve. Compared with the single pass deformation, relative softening degree is9.42%after two passes,33.07%after three passes and24.5%after four passes. It can be investigated that the relative softening degree is the maximum after three passes. The reason for the fall of softening degree after four passes is that the dynamic hardening increases at the same time.
The performance controllability of the panel component produced by rare-earth metals added into magnesium-based alloy with variable wall thickness was studied from the prospectives of plastic strains, grain sizes and forming damage, while the shape controllability of the component was analyzed by the means of forming load when the metal filling reaches full. This paper applies the Lorentz curve and Geordie Coefficient into the deformation uniformity of the forming component. Three aspects including straining, grain size, and damage factor are considered as evaluation factors of the deformation uniformity for the forming component. The objective function of multi-objective optimization problem with three forming uniformity evaluation factors and forming load is established based on the diameters of two Diversion holes, blank thickness for extrusion, forming temperature and speed as variables. By means of orthogonal test, finite element modeling, grey incidence coefficient calculation and AHP (analytical hierarchy process), the weight distribution and grey correlation degrees of the objective function can be realized. And the forming parameters combination from multi-objective optimization can be obtained according to the numerical value of correlation degree.
Finally, on the basis of the optimized parameters combination, the forming controlling dies were designed, and the multiple passes pre-deformation and final forming technology of the panel component produced by rare-earth metals added into magnesium alloy with variable wall thickness were fabricated, and then the technology was validated. The forming component with even properties meets the properties and dimensional requirements in the design, which is a strong technical support for the wider applications of magnesium alloys added with rare-earth metals.
引文
[1]钟皓,刘培英,周铁涛.镁及镁合金在航空航天中的应用及前景[J].航空工程与维修,2002.
[2]张津,章宗和.镁合金及应用[M].北京：化学工业出版社2004,301-304.
[3]张军生,吴迪,王江涛.国产警用38毫米转轮防暴发射器[J].轻兵器,2007.
[4]许小忠,刘强,程军.镁合金在工业及国防中的应用[J].华北工业学院学报,2002,23(3).
[5]黄晓艳,刘波.轻合金是武器装备轻量化的首选金属材料[J].轻合金加工技术,2007.
[6]VonBuch F,Schuman S, Friedrich H,et al.New Die-casting Alloy MRI153 for Power-Train Applications. TMS Annual Meeting,2002:61-67.
[7]Jae Joong Kim, Do Hyang Kim, K S Shin, et al. Modification of Mg2Si Morphology in Squeeze Cast Mg-Al-Zn-Si alloy by Ca or P Addition. Scripta Materialia,1999, 41(3):333-340.
[8]王军,魏霞,向东霞.汽车动力系统用新牌号镁合金.中国镁业,2003,18-24.
[9]L.L.Rokhlin and N.I.Nikitina, Izy. Vyss.Uchebn.Zaved., Tsvetn Metall,.(1),167-168.
[10]P.ManfrinettiandK.A.Gschneidner,Jr,J.Less-common Metals,1986,123(1/2),267-275.
[11]L.L.Rokhlin Magnesium Alloys Containing Rare Earth Metals,Moscow Russia,2003.
[12]Masalski T B, William W. Binary Alloy Phase Diagrams. Second Edition. Scot, Jr,1990.
[13]Drits M E,Rokhlin L.L.Izv. Vyss.Uchebn.Zaved. Tsvetn.Metall.1977,1:168-171.
[14]Drits M E,Sviderskaya Z A,Rokhlin L.L. in Metallurgiya, Metallovedenie i Fiziko-Khimicheskie Metody Issledovaniya. Russian Academy of sciences Publisher,1962,12:143-151.
[15]康煜平.金属固态相变及应用[M].北京：化学工业出版社,2007.
[16]罗治平,张少卿,鲁立奇等.热处理对Mg-Nd-Zr挤压合金性能与组织的影响[J].中国稀土学报,1994,12(2)：183-185.
[17]陈振华,变形镁合金[M],北京：化学工业出版社,2005.6
[18]T.J.Pike and B.Noble, J.Less-Common Metals,197330(1),63-74.
[19]B.N.Ovechkin, L.GKlimovich and N.N.Kulakov, Tekhnol legkich spalavov,1978,(1) 13-16
[20]M.Hisa,J.C.Barry and G.L.Dunlop,in proceedings of the third international a magnesium conference, the institute of materials, London,1978,369-379.
[21]D.Mizer and B.C.Peters, Proc.2nd Int.conf.on strength of metals and alloys,Pacific Grove Calif.,1970,Metals Park,OH,2,669-673
[22]D.Mizer and B.C.Peters,Metal.Trans.1972,3,3262-3264
[23]L.L.Rokhlin and I.E.Tarytina,Fiz.Met.Metalloved.,1985,59(6),1188-1193.
[24]M.E.Drits, L.L.Rokhlin and N.I.Nikitina, in Metallovedenie Legkikh Splavov, VILS,Moscow,1985,133-139.
[25]L.L.Rokhlin and N.I.Nikitina,Fiz.Met.Metalloved.,1986,62(4),781-786.
[26]L.L.Rokhlin, N.I.Nikitina, Z.Metallkd.,1994,85(12),819-823.
[27]P.A.Nuttal,T.J.Pike and B.Noble, Metallography,1980,13(1),3-20.
[28]M.E.Drits,L.L.RokhlinandI.E.Tarytina,Izy.Met.Metalloved.,1983,59(6)1188-1193.
[29]J.F. Nie, B.C. Muddle. Precipitation in magnesium alloy WE54 during isothermal ageing at 250°C, Scripta Materialia,1999,40(10):1089-1094.
[30]J.F. Nie, B.C. Muddle. Characterisation of strengthening precipitate phases in a Mg-Y-Nd alloy, Acta Mater.2000,48(8):1691-1703.
[31]C. Antion, P. Donnadieu, F. Perrard, A. Deschamps, C. Tassin, A. Pisch. Hardening precipitation in a Mg-4Y-3RE alloy, Acta Mater.2003,51(18):5335-5348.
[32]P.J. Apps, H. Karimzadeh, J.F. King, G.W. Lorimer. Precipitation reactions in magnesium-rare earth alloys containing yttrium, gadolinium or dysprosium, Scripta Mater.2003,48(8):1023-1028.
[33]S. Kamado, Y. Kojima, R. Ninomiya, K. Kubota. Aging Characteristics and High TemperatureTensile Properties of Magnesium Alloys Containing Heavy Rare Earth Elements, In:GW.Lorimer(Ed.), Proceedings of the 3rd International Magnesium Conference, Manchester, UK,1996;Institute of Materials,1997,327-342.
[34]Ando S, Tanaka M, Tonda H. Pyramidal slip in magnesium alloy single crystals. Materials Science Forum,2003,419-422:.
[35]Staroselsky A, Anand L. A constitutive model for hcp materials deforming by slip and twinning:application to magnesium alloy AZ31B. International Journal of Plasticity, 2003,1840-1843.
[36]杨春花.镁合金塑性变形中孪生的研究.[D].长沙：湖南大学2006.
[37]陈振华.变形镁合金[M].北京：化学工业出版社,2005.6.
[38]吕宜振.Mg2A12Zn合金组织、性能、变形和断裂行为研究[D].上海：上海交通大学,2001.8.
[39]闫亮明,沈健,李周兵,李俊鹏.Al-Zn-Mg-Cu-Zr合金多道次热轧模拟[J].中国有色金属学报,2012,4(1)：1013-1018.
[40]孟模.铸态AZ80镁合金多次变形工艺及力学行为研究[D].太原：中北大学,2012.
[41]杨续跃,孙争艳,张雷.室温多向多道次压缩变形制备亚微米和纳米级镁合金[J].金属学报,201 0,No5(46)：607-612.
[42]秦勇.多道次热变形的静态软化行为[J].四川冶金,1992,15(3)：55-58.
[43]徐烽.多向锻造变形对ZK60镁合金组织和性能影响研究[D]南京：南京理工大学,2011.
[44]J. H. Hollonman. Tensile Deformation. Trans AIME,1945,162:268-290.
[45]C. M. Sellars. Modelling microstructural development during hot rolling. Materials Science andTechnology,1990,6:1072-1081.
[46]C. M. Sellars. Computer modeling of hot-working processes. Materials Science and Technology.1985,1:325-332.
[47]H. Merking, U. F. Kocks. Kinetics of flow and strain hardening. Acta Metallurgica, 1981,28:1865-1875.
[48]Y. Estrin, H. Merking. A unified phenomenological description of work hardening and creep based on one-parameter model. Acta Metallurgica,1984.32(]):57-70.
[49]Y. Estrin, H. Braasch,Y. Brechet. A dislocation density based constitutive model for cyclic deformation. Journal of Engineering Materials and Technology,1996. 118(4):441-447.
[50]H. J. Frost M. F. Ashby. Deformation mechanism maps[M]. Pergamon Press,1982.
[51]A. Galiyev,0. Sitdikov, R. Kaibyshev. Deformation behavior and controlling mechanisms for plastic flow of magnesium and magnesium alloy. Materials Transactions,2003,44(4):426-435.
[52]H. Takuda, H. Fujimoto, N. Hatta. Modeling on flow stress of Mg-Al-Zn alloys at elevated temperatures. Journal of Materials Processing Technology, 1998.80(82):513-516
[53]T.Sakai,J.J.Jonas. Dynamicreerystallization:Mechanical and microstructural eonsi derations [J].AetaMetallurgieaMaterialia.1984,32(2):189-209.
[54]MCQUEEN H J,RYAN DConstitutive analysis in hot working[J]. Materials Science and Engineering A,2002,322(1-2):43-63.
[55]SHI H,MCLAREN A J,SELLARS C M. Constitutive equations for high temperature flow stress of aluminum alloys[J]. Journal of Materials Processing Technology,1997, 80-81:513-516.
[56]POIRIER J P. Plastic deformation of crystal[M]. GUAN De-cun,transl. Dalian:Dalian Science and Technology University Press,1989:1.
[57]DANIEL J, WHITTENBERGER. The influence of grain size and composition on slow plastic flow in FeAl between 1100 and 1400 K[J]. Mater Sci Eng A,1986,77:103-113
[58]曾卫东,周义刚,周军等.加工图理论研究进展[J].稀有金属材料与工程,2006,35(5)：673-677.
[59]S. Ghosh. Interpretation of microstructural evolution using dynamic materials modeling[J]. Metallurgical and Materials Transactions A,2000,31(11):2973-2974.
[60]F. Montheillet, J. J. Jonas, K. W. Neale. Modeling of dynamic material behavior:a critical evaluation of the dissipator power co-content approach[J]. Metallurgical and Materials Transactions A,1996,27A:232-236.
[61]D.H. Bae, Y. Kim, I.J. Kim. Thermally stable quasicrystalline phase in a superplastic Mg-Zn-Y-Zr alloy[J]. Materials Letters,2006,60:2190-2193.
[62]余琨,史褆,王日初,等.AZ31镁合金变形行为的热/力模拟[J].中南大学学报：自然科学版,2008,39(2)：216-220.
[63]黄树海,赵祖德,夏志新,等.AZ80合金高温变形行为及加工图[J].稀有金属材料与工程,2010,39(5)：848-852.
[64]Verlinden B, Wouters P, Mcqueen H J. Effect of Homogenization and Precipitation Treatments on the Hot Workability of Aluminum Alloy AA2024[J].Materials Science & Engineering A,1990,A123(2):239-245.
[65]Rao K P, Prasad Y K D V, Hawbolt E B. Study of fractional softening in multi-stage hot deformation[J]. J. Mater. Processing Technol.,1998,77:166.
[66]秦勇.多道次热变形的静态软化行为[J].四川冶金,1992,03,55-58.
[67]Zhou M, Clode M P. Constitutive equations for modelling flow softening due to dynamic recovery and heat generation during plastic deformation[J]. Mechanics of Materials,1998,27:63.
[68]Zhang Hui, Yang Libin, Peng Dashu, Meng Liping. Flow stress equation for multipass hot-rolling of aluminum alloys[J]. Cent. South Technol.,2001,(8):13.
[69]Zhang Hui, Yang Libin, Peng Dashu, Lin Gaoyong. Recrystallization model for hot-rolling of 5182 aluminum alloy [J],Trans. Nonferrous Met. Soc. China,2001,(11):382.
[70]Sang Hyun Cho, Sung Ⅱ Kim, Yeon Chul Yoo.Determination of'no-recrystallization' temperature of Invar alloy by fractional softening measurement during the multistage deformation[J].J.Mater. Sci. Lett.,1997,16:1836.
[71]Field D P, Sample V M, Rader R S. Determination of softening kinetics in a material by measuring the evolution of hot flow stress[J]. J Testing & Evaluation,1994,22:530.
[72]Verlinden B, Wouters P, McQueen H J. Effect of homogenization and precipitation treatments on the hot workability of aluminum alloy AA2024[J], Mater. Sci. Eng.,1990,A123:239.
[73]高岩.Mg_Y_Gd_Zn_Zr镁合金组织_性能及其蠕变行为研究[D].上海：上海交通 大学,2009.
[74]Luo Z.P., Zhang S.Q., High-resolution electron microscopy on the X-Mg 12ZnY phase in a high strength Mg-Zn-Zr-Y magnesium alloy, Journal of Materials Science Letters,2000,19,813-815
[75]郑开云,Mg-Gd-Nd-Zr系高强耐热镁合金组织与性能研究[D]上海：上海交通大学,2008.
[76]Verlinden B, Wouters P, McQueen H J,et al. Effect of different homogenization treatments on the hot workability of aluminum alloy AA2024[J]. Mater. Sci. Eng., 1990,A123:229.
[77]Rao K P, Prasad Y K D V, Hawbolt E B. Study of fractional softening in multi-stage hot deformation[J]. J. Mater. Processing Technol.,1998,77:166.
[78]Ryan N D, McQueen H J. Hot strength and microstructural evolution of 316 stainless steel during simulated multistage deformation by torsion[J].J. Mater. Processing Technol,1993,36:103.
[79]Farag M M, Sellars C M, Tegart W J McG Deformation under hot working conditions[M]. London:Iron &Steel Inst,1968.
[80]McQueen H J, Conrod K, Avramovic-Cingara G. Behaviour of Al alloyed with Fe and Co (<1%) in multi-stage torsion tests while cooling from 500 to 300℃[J], Can. Metal Q.,1993,32:375.
[81]郭强,严红革,陈振华,张辉.ZK60镁合金高温压缩道次间软化规律的研究[J]2006.8(10)：8-11.
[82]张召春.铸态.ZK60镁合金锻造及压缩变形规律的研究[D].长沙：湖南大学,2006.
[83]郭强.镁合金高温单向压缩及多向变形行为研究[D].长沙：湖南大学,2007.
[84]孟模.铸态AZ80镁合金多次变形工艺及力学行为研究[D].太原：中北大学,2012.
[85]林高用,张辉,彭大署.7075铝合金热压缩变形道次间软化规律研究[J]轻合金加工技术,2001,19(2)：22-24.
[86]李俊鹏,沈健,闫晓东,毛柏平,闫亮明.多道次热压缩过程中7050铝合金的再结晶行为[J]中国有色金属学报,2009,19(10)：1754-1758.
[87]Y.Cui, Z.M.Zhang, B.H.Zhang, J.M.Yu,Q.Wang, Effects of Multiple Plastic Deformations on Microstructure and Mechanical Properties of 7A04ultra-high strength Aluminum Alloy. Steel Research international,2010,(81)No.9:442-455
[88]Song R G:material review,14(2000),20-21.
[89]Chia E H,McQueen H J. Microstructure Control in Aluminium Alloy Deformation Recovery and Recrystallization,TMS[C].NewYork,1985,179-220.
[90]Zaidi M A,ShepPard T, DeveloPment Of Microstructure throughout Roll Gap during Rolling of Aluminium Alloys [J].MetalsSci,1982(16):229-238.
[91]赵新海,赵国群,王广春等.基于变形均匀性的锻造预成形优化系统集成[J].机械科学与技术,2005,24(1)：42-44.
[92]李玲.基于预成形的锻造过程微观组织模拟与优化设计方法及应用[D].山东：山东大学,2005.
[93]王广春,赵国群,赵新海等.基于变形均匀性的锻造过程微观组织优化方法及其应用[J].数字制造科学,2005,3(2)：1-20.
[94]吴耀金.镁合金负重轮塑性成形参数多目标优化研究[D].太原：中北大学,2011.
[95]黄恒君.收入不平等变迁特征的探索性分析——基于洛伦兹曲线的动态分解[J].统计与信息论坛,2012,27(10)：25-29.
[96]张俊,吴根洲.“985”高校招生区域公平研究——基于洛伦兹曲线和基尼系数[J].考试研究,2010,6(1)：49-57
[97]齐晗.筋板件筋部充填机理及缺陷研究[D].哈尔滨：哈尔滨工业大学,2010.
[98]Altan. T, Lu. S. Modern forging-equipment, materials and process [M].Defense Industrial Press, China,1982
[99]BoEr. C.R, Rebelo. N, Rydstad. H, et al.Process modelling of metal forming and therrnomenchanical treatment [M].Berlin:Springer-Verlag,1986.
[100]Zhang. D.W, Yang H, Sun Z.C, et al. Influences of fillet radius and draft angle on local loading process of titanium alloy T-shaped components [J].Transactions of Nonferrous Metals Society of China
[101]Wang. J.F, Song. P.F, Zhou. X.E, et al. A study of the microstructure, phase composition,and mechamical propel.ties of extruded Mg-9Er-6Y-xZn-0.6Zr magnesium alloys[J].Journal of Ma_terials Science,2012,47(18):6716-6723.
[102]王强.镁合金高性能车轮省力成形理论与试验研究[D].太原：中北大学,2006.
[103]邓聚龙.灰理论基础(灰色系统理论系列书)[M].武汉：华中科技大学出版社,2002.
[104]唐耀平,陈幼林.层次分析法在高校毕业生择业中的应用[J].零陵学院学报,2004,(6)：191-193.
[105]肖磊,胡松.层次分析法在大学毕业生择业问题中的应用[J].教育时空,2005,(4)：80-83.
[106]姜启源,谢金星.叶俊.数学建模(第三版)[M].高等教育出版社,2003：242-244.
[107]崔亚,张治民,于建民,李素丽.多向挤压模具特点及三通件的成形流动分析[J].精密成形工程,2009.
[108]马庆贤,钟约先,曹起骧.大型锻件夹杂性缺陷的形成及控制锻造工艺[J].清华大学学报(自然科学版),2000,40(5)：13-15.
[109]张效迅,崔振山.大锻件内部空洞热锻闭合的z-c判据及其应用[J].机械工程学报,2009,45(1)：148-152.
[2]张津,章宗和.镁合金及应用[M].北京：化学工业出版社2004,301-304.
[3]张军生,吴迪,王江涛.国产警用38毫米转轮防暴发射器[J].轻兵器,2007.
[4]许小忠,刘强,程军.镁合金在工业及国防中的应用[J].华北工业学院学报,2002,23(3).
[5]黄晓艳,刘波.轻合金是武器装备轻量化的首选金属材料[J].轻合金加工技术,2007.
[6]VonBuch F,Schuman S, Friedrich H,et al.New Die-casting Alloy MRI153 for Power-Train Applications. TMS Annual Meeting,2002:61-67.
[7]Jae Joong Kim, Do Hyang Kim, K S Shin, et al. Modification of Mg2Si Morphology in Squeeze Cast Mg-Al-Zn-Si alloy by Ca or P Addition. Scripta Materialia,1999, 41(3):333-340.
[8]王军,魏霞,向东霞.汽车动力系统用新牌号镁合金.中国镁业,2003,18-24.
[9]L.L.Rokhlin and N.I.Nikitina, Izy. Vyss.Uchebn.Zaved., Tsvetn Metall,.(1),167-168.
[10]P.ManfrinettiandK.A.Gschneidner,Jr,J.Less-common Metals,1986,123(1/2),267-275.
[11]L.L.Rokhlin Magnesium Alloys Containing Rare Earth Metals,Moscow Russia,2003.
[12]Masalski T B, William W. Binary Alloy Phase Diagrams. Second Edition. Scot, Jr,1990.
[13]Drits M E,Rokhlin L.L.Izv. Vyss.Uchebn.Zaved. Tsvetn.Metall.1977,1:168-171.
[14]Drits M E,Sviderskaya Z A,Rokhlin L.L. in Metallurgiya, Metallovedenie i Fiziko-Khimicheskie Metody Issledovaniya. Russian Academy of sciences Publisher,1962,12:143-151.
[15]康煜平.金属固态相变及应用[M].北京：化学工业出版社,2007.
[16]罗治平,张少卿,鲁立奇等.热处理对Mg-Nd-Zr挤压合金性能与组织的影响[J].中国稀土学报,1994,12(2)：183-185.
[17]陈振华,变形镁合金[M],北京：化学工业出版社,2005.6
[18]T.J.Pike and B.Noble, J.Less-Common Metals,197330(1),63-74.
[19]B.N.Ovechkin, L.GKlimovich and N.N.Kulakov, Tekhnol legkich spalavov,1978,(1) 13-16
[20]M.Hisa,J.C.Barry and G.L.Dunlop,in proceedings of the third international a magnesium conference, the institute of materials, London,1978,369-379.
[21]D.Mizer and B.C.Peters, Proc.2nd Int.conf.on strength of metals and alloys,Pacific Grove Calif.,1970,Metals Park,OH,2,669-673
[22]D.Mizer and B.C.Peters,Metal.Trans.1972,3,3262-3264
[23]L.L.Rokhlin and I.E.Tarytina,Fiz.Met.Metalloved.,1985,59(6),1188-1193.
[24]M.E.Drits, L.L.Rokhlin and N.I.Nikitina, in Metallovedenie Legkikh Splavov, VILS,Moscow,1985,133-139.
[25]L.L.Rokhlin and N.I.Nikitina,Fiz.Met.Metalloved.,1986,62(4),781-786.
[26]L.L.Rokhlin, N.I.Nikitina, Z.Metallkd.,1994,85(12),819-823.
[27]P.A.Nuttal,T.J.Pike and B.Noble, Metallography,1980,13(1),3-20.
[28]M.E.Drits,L.L.RokhlinandI.E.Tarytina,Izy.Met.Metalloved.,1983,59(6)1188-1193.
[29]J.F. Nie, B.C. Muddle. Precipitation in magnesium alloy WE54 during isothermal ageing at 250°C, Scripta Materialia,1999,40(10):1089-1094.
[30]J.F. Nie, B.C. Muddle. Characterisation of strengthening precipitate phases in a Mg-Y-Nd alloy, Acta Mater.2000,48(8):1691-1703.
[31]C. Antion, P. Donnadieu, F. Perrard, A. Deschamps, C. Tassin, A. Pisch. Hardening precipitation in a Mg-4Y-3RE alloy, Acta Mater.2003,51(18):5335-5348.
[32]P.J. Apps, H. Karimzadeh, J.F. King, G.W. Lorimer. Precipitation reactions in magnesium-rare earth alloys containing yttrium, gadolinium or dysprosium, Scripta Mater.2003,48(8):1023-1028.
[33]S. Kamado, Y. Kojima, R. Ninomiya, K. Kubota. Aging Characteristics and High TemperatureTensile Properties of Magnesium Alloys Containing Heavy Rare Earth Elements, In:GW.Lorimer(Ed.), Proceedings of the 3rd International Magnesium Conference, Manchester, UK,1996;Institute of Materials,1997,327-342.
[34]Ando S, Tanaka M, Tonda H. Pyramidal slip in magnesium alloy single crystals. Materials Science Forum,2003,419-422:.
[35]Staroselsky A, Anand L. A constitutive model for hcp materials deforming by slip and twinning:application to magnesium alloy AZ31B. International Journal of Plasticity, 2003,1840-1843.
[36]杨春花.镁合金塑性变形中孪生的研究.[D].长沙：湖南大学2006.
[37]陈振华.变形镁合金[M].北京：化学工业出版社,2005.6.
[38]吕宜振.Mg2A12Zn合金组织、性能、变形和断裂行为研究[D].上海：上海交通大学,2001.8.
[39]闫亮明,沈健,李周兵,李俊鹏.Al-Zn-Mg-Cu-Zr合金多道次热轧模拟[J].中国有色金属学报,2012,4(1)：1013-1018.
[40]孟模.铸态AZ80镁合金多次变形工艺及力学行为研究[D].太原：中北大学,2012.
[41]杨续跃,孙争艳,张雷.室温多向多道次压缩变形制备亚微米和纳米级镁合金[J].金属学报,201 0,No5(46)：607-612.
[42]秦勇.多道次热变形的静态软化行为[J].四川冶金,1992,15(3)：55-58.
[43]徐烽.多向锻造变形对ZK60镁合金组织和性能影响研究[D]南京：南京理工大学,2011.
[44]J. H. Hollonman. Tensile Deformation. Trans AIME,1945,162:268-290.
[45]C. M. Sellars. Modelling microstructural development during hot rolling. Materials Science andTechnology,1990,6:1072-1081.
[46]C. M. Sellars. Computer modeling of hot-working processes. Materials Science and Technology.1985,1:325-332.
[47]H. Merking, U. F. Kocks. Kinetics of flow and strain hardening. Acta Metallurgica, 1981,28:1865-1875.
[48]Y. Estrin, H. Merking. A unified phenomenological description of work hardening and creep based on one-parameter model. Acta Metallurgica,1984.32(]):57-70.
[49]Y. Estrin, H. Braasch,Y. Brechet. A dislocation density based constitutive model for cyclic deformation. Journal of Engineering Materials and Technology,1996. 118(4):441-447.
[50]H. J. Frost M. F. Ashby. Deformation mechanism maps[M]. Pergamon Press,1982.
[51]A. Galiyev,0. Sitdikov, R. Kaibyshev. Deformation behavior and controlling mechanisms for plastic flow of magnesium and magnesium alloy. Materials Transactions,2003,44(4):426-435.
[52]H. Takuda, H. Fujimoto, N. Hatta. Modeling on flow stress of Mg-Al-Zn alloys at elevated temperatures. Journal of Materials Processing Technology, 1998.80(82):513-516
[53]T.Sakai,J.J.Jonas. Dynamicreerystallization:Mechanical and microstructural eonsi derations [J].AetaMetallurgieaMaterialia.1984,32(2):189-209.
[54]MCQUEEN H J,RYAN DConstitutive analysis in hot working[J]. Materials Science and Engineering A,2002,322(1-2):43-63.
[55]SHI H,MCLAREN A J,SELLARS C M. Constitutive equations for high temperature flow stress of aluminum alloys[J]. Journal of Materials Processing Technology,1997, 80-81:513-516.
[56]POIRIER J P. Plastic deformation of crystal[M]. GUAN De-cun,transl. Dalian:Dalian Science and Technology University Press,1989:1.
[57]DANIEL J, WHITTENBERGER. The influence of grain size and composition on slow plastic flow in FeAl between 1100 and 1400 K[J]. Mater Sci Eng A,1986,77:103-113
[58]曾卫东,周义刚,周军等.加工图理论研究进展[J].稀有金属材料与工程,2006,35(5)：673-677.
[59]S. Ghosh. Interpretation of microstructural evolution using dynamic materials modeling[J]. Metallurgical and Materials Transactions A,2000,31(11):2973-2974.
[60]F. Montheillet, J. J. Jonas, K. W. Neale. Modeling of dynamic material behavior:a critical evaluation of the dissipator power co-content approach[J]. Metallurgical and Materials Transactions A,1996,27A:232-236.
[61]D.H. Bae, Y. Kim, I.J. Kim. Thermally stable quasicrystalline phase in a superplastic Mg-Zn-Y-Zr alloy[J]. Materials Letters,2006,60:2190-2193.
[62]余琨,史褆,王日初,等.AZ31镁合金变形行为的热/力模拟[J].中南大学学报：自然科学版,2008,39(2)：216-220.
[63]黄树海,赵祖德,夏志新,等.AZ80合金高温变形行为及加工图[J].稀有金属材料与工程,2010,39(5)：848-852.
[64]Verlinden B, Wouters P, Mcqueen H J. Effect of Homogenization and Precipitation Treatments on the Hot Workability of Aluminum Alloy AA2024[J].Materials Science & Engineering A,1990,A123(2):239-245.
[65]Rao K P, Prasad Y K D V, Hawbolt E B. Study of fractional softening in multi-stage hot deformation[J]. J. Mater. Processing Technol.,1998,77:166.
[66]秦勇.多道次热变形的静态软化行为[J].四川冶金,1992,03,55-58.
[67]Zhou M, Clode M P. Constitutive equations for modelling flow softening due to dynamic recovery and heat generation during plastic deformation[J]. Mechanics of Materials,1998,27:63.
[68]Zhang Hui, Yang Libin, Peng Dashu, Meng Liping. Flow stress equation for multipass hot-rolling of aluminum alloys[J]. Cent. South Technol.,2001,(8):13.
[69]Zhang Hui, Yang Libin, Peng Dashu, Lin Gaoyong. Recrystallization model for hot-rolling of 5182 aluminum alloy [J],Trans. Nonferrous Met. Soc. China,2001,(11):382.
[70]Sang Hyun Cho, Sung Ⅱ Kim, Yeon Chul Yoo.Determination of'no-recrystallization' temperature of Invar alloy by fractional softening measurement during the multistage deformation[J].J.Mater. Sci. Lett.,1997,16:1836.
[71]Field D P, Sample V M, Rader R S. Determination of softening kinetics in a material by measuring the evolution of hot flow stress[J]. J Testing & Evaluation,1994,22:530.
[72]Verlinden B, Wouters P, McQueen H J. Effect of homogenization and precipitation treatments on the hot workability of aluminum alloy AA2024[J], Mater. Sci. Eng.,1990,A123:239.
[73]高岩.Mg_Y_Gd_Zn_Zr镁合金组织_性能及其蠕变行为研究[D].上海：上海交通 大学,2009.
[74]Luo Z.P., Zhang S.Q., High-resolution electron microscopy on the X-Mg 12ZnY phase in a high strength Mg-Zn-Zr-Y magnesium alloy, Journal of Materials Science Letters,2000,19,813-815
[75]郑开云,Mg-Gd-Nd-Zr系高强耐热镁合金组织与性能研究[D]上海：上海交通大学,2008.
[76]Verlinden B, Wouters P, McQueen H J,et al. Effect of different homogenization treatments on the hot workability of aluminum alloy AA2024[J]. Mater. Sci. Eng., 1990,A123:229.
[77]Rao K P, Prasad Y K D V, Hawbolt E B. Study of fractional softening in multi-stage hot deformation[J]. J. Mater. Processing Technol.,1998,77:166.
[78]Ryan N D, McQueen H J. Hot strength and microstructural evolution of 316 stainless steel during simulated multistage deformation by torsion[J].J. Mater. Processing Technol,1993,36:103.
[79]Farag M M, Sellars C M, Tegart W J McG Deformation under hot working conditions[M]. London:Iron &Steel Inst,1968.
[80]McQueen H J, Conrod K, Avramovic-Cingara G. Behaviour of Al alloyed with Fe and Co (<1%) in multi-stage torsion tests while cooling from 500 to 300℃[J], Can. Metal Q.,1993,32:375.
[81]郭强,严红革,陈振华,张辉.ZK60镁合金高温压缩道次间软化规律的研究[J]2006.8(10)：8-11.
[82]张召春.铸态.ZK60镁合金锻造及压缩变形规律的研究[D].长沙：湖南大学,2006.
[83]郭强.镁合金高温单向压缩及多向变形行为研究[D].长沙：湖南大学,2007.
[84]孟模.铸态AZ80镁合金多次变形工艺及力学行为研究[D].太原：中北大学,2012.
[85]林高用,张辉,彭大署.7075铝合金热压缩变形道次间软化规律研究[J]轻合金加工技术,2001,19(2)：22-24.
[86]李俊鹏,沈健,闫晓东,毛柏平,闫亮明.多道次热压缩过程中7050铝合金的再结晶行为[J]中国有色金属学报,2009,19(10)：1754-1758.
[87]Y.Cui, Z.M.Zhang, B.H.Zhang, J.M.Yu,Q.Wang, Effects of Multiple Plastic Deformations on Microstructure and Mechanical Properties of 7A04ultra-high strength Aluminum Alloy. Steel Research international,2010,(81)No.9:442-455
[88]Song R G:material review,14(2000),20-21.
[89]Chia E H,McQueen H J. Microstructure Control in Aluminium Alloy Deformation Recovery and Recrystallization,TMS[C].NewYork,1985,179-220.
[90]Zaidi M A,ShepPard T, DeveloPment Of Microstructure throughout Roll Gap during Rolling of Aluminium Alloys [J].MetalsSci,1982(16):229-238.
[91]赵新海,赵国群,王广春等.基于变形均匀性的锻造预成形优化系统集成[J].机械科学与技术,2005,24(1)：42-44.
[92]李玲.基于预成形的锻造过程微观组织模拟与优化设计方法及应用[D].山东：山东大学,2005.
[93]王广春,赵国群,赵新海等.基于变形均匀性的锻造过程微观组织优化方法及其应用[J].数字制造科学,2005,3(2)：1-20.
[94]吴耀金.镁合金负重轮塑性成形参数多目标优化研究[D].太原：中北大学,2011.
[95]黄恒君.收入不平等变迁特征的探索性分析——基于洛伦兹曲线的动态分解[J].统计与信息论坛,2012,27(10)：25-29.
[96]张俊,吴根洲.“985”高校招生区域公平研究——基于洛伦兹曲线和基尼系数[J].考试研究,2010,6(1)：49-57
[97]齐晗.筋板件筋部充填机理及缺陷研究[D].哈尔滨：哈尔滨工业大学,2010.
[98]Altan. T, Lu. S. Modern forging-equipment, materials and process [M].Defense Industrial Press, China,1982
[99]BoEr. C.R, Rebelo. N, Rydstad. H, et al.Process modelling of metal forming and therrnomenchanical treatment [M].Berlin:Springer-Verlag,1986.
[100]Zhang. D.W, Yang H, Sun Z.C, et al. Influences of fillet radius and draft angle on local loading process of titanium alloy T-shaped components [J].Transactions of Nonferrous Metals Society of China
[101]Wang. J.F, Song. P.F, Zhou. X.E, et al. A study of the microstructure, phase composition,and mechamical propel.ties of extruded Mg-9Er-6Y-xZn-0.6Zr magnesium alloys[J].Journal of Ma_terials Science,2012,47(18):6716-6723.
[102]王强.镁合金高性能车轮省力成形理论与试验研究[D].太原：中北大学,2006.
[103]邓聚龙.灰理论基础(灰色系统理论系列书)[M].武汉：华中科技大学出版社,2002.
[104]唐耀平,陈幼林.层次分析法在高校毕业生择业中的应用[J].零陵学院学报,2004,(6)：191-193.
[105]肖磊,胡松.层次分析法在大学毕业生择业问题中的应用[J].教育时空,2005,(4)：80-83.
[106]姜启源,谢金星.叶俊.数学建模(第三版)[M].高等教育出版社,2003：242-244.
[107]崔亚,张治民,于建民,李素丽.多向挤压模具特点及三通件的成形流动分析[J].精密成形工程,2009.
[108]马庆贤,钟约先,曹起骧.大型锻件夹杂性缺陷的形成及控制锻造工艺[J].清华大学学报(自然科学版),2000,40(5)：13-15.
[109]张效迅,崔振山.大锻件内部空洞热锻闭合的z-c判据及其应用[J].机械工程学报,2009,45(1)：148-152.
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