U-5.7Nb合金绝热剪切带微观组织结构特征  

Microstructural Characterization of Adiabatic Shear Band in U-5.7Nb Alloy

作　　者：赵雅文[1] 刘柯钊[2] 肖大武[1] 何立峰[1] 石洁[2] 邹东利[1] 

机构地区：[1]中国工程物理研究院,四川绵阳621900 [2]表面物理与化学重点实验室,四川绵阳621907

出　　处：《稀有金属材料与工程》2017年第2期484-490,共7页Rare Metal Materials and Engineering

基　　金：中国工程物理研究院发展基金(2015B0301066);国家自然科学基金(51401187)

摘　　要：利用SHPB实验装置对U-5.7Nb合金帽型样品在室温下进行动态加载,获得U-5.7Nb合金绝热剪切带,采用激光共聚焦、SEM、纳米压痕以及TEM等测试方法开展了U-5.7Nb合金绝热剪切带内组织结构的研究。U-5.7Nb合金绝热剪切带宽约40μm,且呈现蚀刻"暗带";剪切带内微裂纹的萌生和扩展导致带内"破碎"等轴晶特征组织的出现;剪切带核心区域出现取向高度异性的纳米"晶畴"。剪切带内特殊的组织结构变化导致剪切带硬度与弹性模量的不同变化趋势。The microstructure in adiabatic shear band（ASB） of U-5.7Nb alloy deformed at high strain rate by a split Hopkinson pressure bar（SHPB） was investigated by OM,SEM and TEM.We observed the ASB with black etching color in U-5.7Nb,and its width is about 40 μm.The evolution of microcracks in ASB leads to the formation of the micro-feature which like equiaxed ＂broken grain＂ with the size of 2～5 μm in ASB.The nano-sized grain domains below 5 nm are found in the core of ASB,and the orientations of single small grain domains differ completely,even within an area of 1 μm.Microhardness of the ASB is higher than that of the matrix,but elastic modulus of ASB is lower than that of the matrix.The different trends between microhardness and elastic modulus are caused by the change of micro structure in ASB.

关 键 词：U-5.7Nb合金 微观组织 绝热剪切带 Hopkinson TEM 

分 类 号：TG146.8[一般工业技术—材料科学与工程]