偏共析U-Nb合金的变形及应变回复行为

Deformation and Strain Recovery Behavior of U-Nb Alloy near the Monotectoid Composition

对U-Nb合金施加不同程度的预应变后,利用自制的变形测量装置研究该合金在加热时的应变回复行为,结合透射电子显微镜(TEM)、X射线衍射(XRD)仪等对U-Nb合金的变形机制及形状记忆效应进行探讨。结果表明:高密度的孪晶组织在变形时的相互吞并、长大及择优取向是该合金在形变初期的主要变形机制,并认为U-Nb合金具有显著的形状记忆效应(SME),在加热过程中,其最大应变回复量可达3.2%,升温时粗大的孪晶组织通过逆相变重新取向和分解是导致该合金具有形状记忆效应的主要原因。

Pre-deformation to various degrees was imposed to the U-Nb alloy;afterwards the strain-recovery behavior of the alloy was investigated by the self-made strain-measuring equipment.The deformation mechanism and shape memory effect（SME） of the U-Nb alloy were investigated by TEM and XRD.The results show that growth,swallow and preferred orientation of high density twins is the primary deformation mechanism for U-Nb alloy at the initial stage of deformation,and it is considered that U-Nb alloy possesses excellent shape memory effect.The maximum reversible strain reaches to 3.2% during heating;reorientation and splitting through phase reversion of enlarged twins during reheating is the main reason for the shape memory effect of U-Nb alloy.