两种典型初始取向Mg-11Gd-3Y-0.5Nd-Zr合金的动态再结晶行为
Dynamic Recrystallization Behavior of Mg-11Gd-3Y-0.5Nd-Zr Alloy with Two Typical Initial Orientations
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摘要: 对锻态Mg-11Gd-3Y-0.5Nd-Zr合金进行520 ℃×18 h的退火,再分别沿平行于和垂直于锻造方向取样(0°,90°试样)并沿试样轴向进行高温压缩,研究了不同变形量(25%,50%,70%)高温压缩过程中的动态再结晶行为,分析了塑性变形机制及其对动态再结晶的影响。结果表明:随着变形量增加,0°试样和90°试样的动态再结晶面积分数均逐渐增大;90°试样的动态再结晶面积分数相比0°试样更小,尤其在变形量50%下二者相差最大;0°试样和90°试样的塑性变形机制均为棱柱面滑移;90°试样的无滑移系启动晶粒数量相比0°试样更少,棱柱面滑移施密特因子更接近0.5,小角度晶界密度更大,接近1的晶间变形协调因子占比更大,说明其滑移更容易启动,晶间变形协调能力也更强,变形更分散,更难激活动态再结晶。Abstract: The forged Mg-11Gd-3Y-0.5Nd-Zr alloy was annealed at 520 ℃ for 18 h. Then the 0° sample and 90° sample were taken parallel to and perpendicular to the forging direction respectively, and hot compression was carried out along the sample axial direction. The dynamic recrystallization behavior of the samples under hot compression with different deformation (25%, 50%, 70%) was studied. The mechanism of plastic deformation and its influence on dynamic recrystallization were analyzed. The results show that the dynamic recrystallization area fraction of the 0° sample and 90° sample increased with the increase of the deformation. The dynamic recrystallization area fraction of 90° sample was smaller than that of 0° sample, especially when the deformation was 50% the difference between those two was largest. The plastic deformation mechanism of 0° sample and 90° sample was prismatic plane slip. The number of initiating grains of the non-slip system of 90° sample was less comparied to that of 0° sample, the Schmidt factor for prismatic plane slip was closer to 0.5, the low angle grain boundary density was larger, and the proportion of intergranular deformation coordination factor close to 1 was larger, indicating that the slip of the 90° sample was easier to start, the intergranular deformation coordination ability was stronger, the deformation was more dispersed, and was more difficult to activate dynamic recrystallization.