Optimization of the Mg-Al-Zn-Ca-Sr alloy composition based on the parameter A鈥?in the constitutive equation for the climb-controlled dislocation creep including the stacking fault energy

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• 作者：Kinji Hirai^a ; ^{kinji.hirai@takata.co.jp} ; ^{kinji.hirai@kanagawa.email.ne.jp} ; Ippei Takeuchi^b ; Yorinobu Takigawa^b ; Tokuteru Uesugi^b ; Kenji Higashi^b
• 关键词：Mg&ndash ; Al&ndash ; Zn&ndash ; Ca&ndash ; Sr magnesium alloys ; Creep resistance ; Die-cast ; Constitutive equation ; Stacking fault energy ; Microstructure
• 刊名：Materials Science and Engineering ; A
• 出版年：2012
• 期刊代码：61_09215093
• 类别：ms
• 出版时间：15 August, 2012
• 卷：551
• 期：Complete
• 页码：19-24
• 文件大小：1170 K

摘要

In this study, calcium, Ca-, and strontium, Sr-added AZ91 magnesium alloys, which were composed of magnesium, Mg-9 wt.%aluminum, Al-0.8 wt.%zinc, Zn-x wt.%Ca-y wt.%Sr, were formulated and designated as AZXJ91xy alloys. The optimum composition of die-cast AZXJ alloys has been studied by micro-structural analysis and through the application of the constitutive equation of deformation behavior at elevated temperatures that includes the stacking fault energy. The normalized plots of the tensile test results of AZXJ alloys at 448 K by the constitutive equation of deformation behavior indicated that the deformation mechanism of the alloys was climb-controlled dislocation creep. The value of the constant A鈥?in the constitutive equation differs in the different AZXJ alloys, even though the effect of the solid solution of added elements, which is considered in the stacking fault energy term, was eliminated from A鈥? Using A鈥?as an indicator parameter of the creep resistance with the tensile strength at ambient temperature, the optimum composition of the creep-resistant Mg-Al-Zn-Ca-Sr alloy has been determined, and its creep resistance was comparable to those of known heat-resistant magnesium alloys.