【作者】 赵欣； 张奎； 李兴刚； 李永军； 何庆彪； 孙建锋；

【Author】 Zhao Xin~1 Zhang Kui~1 Li Xing-gang~1 Li Yong-jun~1 He Qing-kui~2 Sun Jian-feng~2 (1.State Key Laboratory for Fabrication and Processing of Non-Ferrous Metals General Research Institute for Non-ferrous Metals,Beijing100088,China; 2.The 518th Institute No.5 Academy of China Aerospace Science & Technology Corporarion,Shanxi,030800,China)

【机构】 北京有色金属研究总院有色金属材料制备加工国家重点实验室； 中国航天科技集团公司第五研究院第五一八研究所；

【摘要】 在温度为250～450℃、应变速率为0.002伍1s^-1、最大变形程度为50%的条件下,采用 GLEEBLE-1500热模拟机对 Mg-Gd-Y-Nd-Zr 镁合金进行了高温压缩实验研究。从真应力-真应变曲线上得到了应变硬化率（θ）,分别得到了在不同压缩条件下的θ-σ、-（（?）θ/■σ）-σ和 lnθ-σ。结果表明:动态再结晶开始发生的临界条件满足（（■/■σ）（-■θ/■σ））=0,发现动态再结晶开始的临界应力、临界应变与峰值应力、峰值应变的比值在一定范围内变化,动态再结品过程在真应力-真应变曲线峰值点之前就开始发生,并且临界应变可以用 Zener-Hollomon 参数的幂指数形式进行描述。通过金相显微组织研究了该镁合金在不同温度和不同应变速率下的组织演变,采用截线法测量平均晶粒尺寸。结果表明:再结晶晶粒的平均晶粒尺寸随温度的升高、应变速率的减小而增大;随温度的降低应变速率的增大而减小,并且平均晶粒尺寸的自然对数 Zener-Hollomon 参数的自然对数成线性关系;峰值应力随平均晶粒尺寸的减小而增大,随平均品粒尺寸的增大而减小,并且平均晶粒尺寸的自然对数与峰值应力的自然对数成线性关系。更多还原

【Abstract】 Hot compression tests of Mg-Gd-Y-Nd-Zr RE-containing magnesium alloy are performed on Gleeble 1500 at strain rates ranged in 0.002～1s^-1and deformation temperature 250～450℃ under the deformation degree of 50%.The stain-hardening rate can be obtained from true stress-true strain curves,the plots of θ-σ, -（（?）θ/（?）σ）-σand Inθ-σ in the different compression condition are obtained by the further study.The results show that the critical condition of the onset of DRX process is following as （（（?）/（?）σ）（-（?）θ/（?）σ））=0,the ratio of the critical stress to the peak stress and the critical strain to the peak strain stands at the definite range variably,the onset of DRX process occurred before the peak of the stress-strain flow curves,and the natural logarithm of the critical strain is linear with the natural logarithm of Zener-Hollomon parameter.The texture evolution of the magnesium alloy in the different temperature and strain rates is studied by the metallurgical structure,the recrystallization average gain size is measured using the means of transversal.The results show that the recrystallization average gain size enlarges following the temperature increases and the strain rates decreases and the opposite is right,the natural logarithm of the recrystallization average gain size is linear with the natural logarithm of Zener-Hollomon parameter;the peak stress enlarges following the decreasement of the recrystallization average gain size and the opposite is right,and the natural logarithm of the recrystallization average gain size is linear with the natural logarithm of the peak stress.更多还原