Mg-Y-Nd-Gd-Zr合金动态再结晶实验研究  

Experimental Study on Recrystallization of Mg-Y-Nd-Gd-Zr Alloy

作　　者：赵欣[1] 张奎[1] 李兴刚[1] 李永军[1] 何庆彪[2] 孙建锋[2] 

机构地区：[1]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,北京100088 [2]中国航天科技集团公司第五研究院第五一八研究所,山西太原030800

出　　处：《稀有金属》2008年第5期567-573,共7页Chinese Journal of Rare Metals

基　　金：国家“十一五”支撑计划项目(2006BAE04B01,2006BAE04B04)

摘　　要：在温度为523～723K,应变速率为0.002～1s-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),分别绘制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,动态再结晶过程在真应力-真应变曲线峰值点之前就开始发生。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;峰值应力随平均晶粒尺寸的减小而增大,随平均晶粒尺寸的增大而减小。Hot compression tests of Mg-Gd-Y-Nd-Zr RE-containing magnesium alloy were performed using Gleeble1500 test equipment at the strain rate within the range of 0. 002 - 1 s^-1 and the deformation temperature of 523 - 723 K under the deformation degree of 50%. The stain-hardening rate could be obtained from true stress-true strain curves, the plots of θ-σ, -（δθ/δσ）-σ and -lnθ-σ under the different compression conditions were obtained through the agency of this study. The results showed that the critical condition of the onset of DRX process was （（ δ/δσ） （-δθ/δσ）） = 0, the ratios of the critical stress to the peak stress and the critical strain to the peak strain stands were variable in the definite range, the onset of DRX process occurred before the peak of the stressstrain flow curves. The texture evolution of magnesium alloy at the different temperatures and strain rates were studied by the metallographic observation, the recrys- tallization average gain size was measured using the intercept method. The results showed that the recrystallization average grain size was enlarging with the temperature increasing and the strain rates decreasing and their opposite results presented; the peak stress enlarged following the decrease of the recrystallization average gain size and the opposite one also did.

关 键 词：稀土镁合金 热压缩变形 动态再结晶 应变硬化率 平均晶粒尺寸 

分 类 号：TM911.4[电气工程—电力电子与电力传动]