High cycle fatigue behavior of Ti-5Al-5Mo-5V-3Cr-1Zr titanium alloy with lamellar microstructure

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• 作者：Chaowen Huang^a ; ^b ; ^{huangchaowen318@163.com} ; Yongqing Zhao^a ; ^b ; ^{trc@c-nin.com} ; Shewei Xin^b ; Changsheng Tan^c ; Wei Zhou^b ; Qian Li^b ; Weidong Zeng^a
• 关键词：Ti&ndash ; 55531 titanium alloy ; Microstructure ; High&ndash ; cycle fatigue ; Crack initiation ; Crack propagation
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：13 January 2017
• 年：2017
• 卷：682
• 期：Complete
• 页码：107-116
• 全文大小：7445 K
• 卷排序：682

文摘

High–cycle fatigue (HCF) damage behavior of Ti–5Al–5Mo–5V–3Cr–1Zr (Ti–55531) titanium alloy with lamellar microstructure (LM) was systematically investigated at room temperature. Results indicate that both grain boundary (GB) α phase and small–scale (~10 µm) heterogeneous microstructure regions (SHMRs) in prior β grains are weak microstructures in LM. Microcracks nucleate at prior β GBs caused by fracturing of some GB α during HCF loading. Dislocations nucleate and annihilate at α/β interfaces, which promote strain concentration and microcracks initiation at α/β interfaces in SHMRs. A combination of slip and twinning predominate cyclic deformation in α lamellae, which leads to nucleation of microcracks at α lamellae in SHMRs. Small cracks grow along α/β interfaces or transfer across α lamellae, and then form relatively long cracks in β grain interiors. Such crack initiation and propagation behaviors promote the HCF fracture of the alloy.