挤压扭转复合形变钨合金绝热剪切带内动态再结晶机制研究(英文)  

Dynamic Recrystallization in the Shear Bands of Tungsten Heavy Alloy Processed by Hot-Hydrostatic Extrusion and Hot Torsion

作　　者：刘金旭[1] 李树奎[1] 周晓青[1] 王迎春[1] 杨佳[1] 

机构地区：[1]北京理工大学,北京100081

出　　处：《稀有金属材料与工程》2011年第6期957-960,共4页Rare Metal Materials and Engineering

摘　　要：对烧结态钨合金进行热挤压、热扭转复合变形,采用分离式霍普金森杆对其进行单轴动态压缩加载,试样发生绝热剪切破坏,表明复合形变后钨合金的绝热剪切敏感性大幅度提高,通过控制加载应变率,获得具有不同演化阶段但未发生破坏的绝热剪切带,采用透射电镜分析绝热剪切带内的微观演化过程,分析绝热剪切带内的动态再结晶机制。结果表明,钨合金绝热剪切带内的组织演化以位错机制为基础,没有孪晶参与,细小的等轴再结晶晶粒通过重复位错增殖、重排和湮灭等过程形成,其动态再结晶行为属于亚晶旋转动态再结晶机制。Hot-hydrostatic extrusion and hot torsion（HE＋HT） were applied to the processing of the as-sintered tungsten heavy alloy（WHA）.The dynamic mechanical properties of the WHA processed by HE＋HT and the microstructural evolution within adiabatic shear band（ASB） were systematically investigated.The results show that the WHA susceptibility to ASB is much improved,and localized shear bands can be formed in specimens.TEM analysis of ASB shows that the multiplication and rearrangement of dislocation play dominate roles in the dynamic recrystallization（DRX） process within ASB of WHA,and the nano-scaled equiaxed-recrystallized grains within ASB can be formed via repeating the processes including dislocation multiplication,dislocation rearrangement and dislocation annihilation.The investigation result of observed DRX of the WHA firmly supports the rotational dynamic recrystallization（RDR） mechanism in metals.

关 键 词：钨合金 动态再结晶 绝热剪切带 动态压缩 

分 类 号：TG111.7[金属学及工艺—物理冶金]