Effects of cryogenic temperature and pre-stretching on mechanical properties and deformation characteristics of a peak-aged AA6082 extrusion

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• 作者：Zebing Xu^a ; Hans J. Roven^a ; ^{hans.j.roven@material.ntnu.no" class="auth_mail" title="E-mail the corresponding author} ; Zhihong Jia^b
• 关键词：AA6082 alloy ; Cryogenic temperature ; Mechanical properties ; Pre-stretching ; Homogenous deformation ; Slip localization
• 刊名：Materials Science & Engineering A
• 出版年：2017
• 出版时间：2 January 2017
• 年：2017
• 卷：679
• 期：Complete
• 页码：379-390
• 全文大小：3029 K

文摘

Plastic deformation studies of a peak-aged AA6082 alloy by means of tensile tests at 77 K and 295 K, and related microstructure characteristics obtained by Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD), Transmission Electron Microscopy (TEM) and Atom Force Microscopy (AFM), revealed new results. A simultaneous improvement in ductility and strength occurred at 77 K, but not at 295 K. A higher work hardening accompanied by a more homogeneous slip mode explained the improved properties at 77 K. Pre-stretching at these two temperatures and subsequent tensile testing at room temperature revealed a marked yield point. However, pre-stretching at 77 K exhibited a slightly higher room temperature yield strength and ductility than the condition pre-stretched at 295 K. Annealing after pre-stretching improved ductility and reduced the magnitude of the yield point. Pre-stretching at 77 K and subsequent annealing introduced somewhat higher strength and ductility as compared to the counterpart pre-stretched at 295 K. The observed mechanical behaviour and associated phenomena were directly linked to microstructure characteristics such as deformation substructure history, slip localization, dislocation density and the precipitate β^' /β^'' ratio.