定向再结晶对热轧态Cu71Al18Mn11合金的组织和超弹性性能的影响  

Effects of Directional Recrystallization on Microstructure and Superelastic Property of Hot-rolled Cu71Al18Mn11 Alloy

作　　者：徐利君 郑策 冯小辉[1] 黄秋燕 李应举[1] 杨院生[1] XU Lijun;ZHENG Ce;FENG Xiaohui;HUANG Qiuyan;LI Yingju;YANG Yuansheng(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《材料研究学报》2023年第8期571-580,共10页Chinese Journal of Materials Research

基　　金：国家重点研发计划(2018YFE0115800)。

摘　　要：对75%变形量热轧态Cu71Al18Mn11合金进行热区温度分别为800、850和900℃和抽拉速度分别为2、5和15μm/s的正交定向再结晶实验,研究工艺参数对热轧态Cu71Al18Mn11合金的定向再结晶组织和超弹性性能的影响,并分析定向再结晶机理。结果表明:随着抽拉速度的提高,定向再结晶的效果呈现先增强后减弱的趋势。抽拉速度为2μm/s时为粗大等轴晶中掺杂着少量柱状晶的组织,抽拉速度提高到5μm/s时可获得大长径比柱状晶组织,但抽拉速度提高至15μm/s时则定向再结晶组织为柱状晶与等轴晶混合组织。大长径比柱状晶组织的合金其超弹性性能较好,900℃-5μm/s定向再结晶合金的应变量为12%时残余应变仅为1.1%,超弹性应变为9.05%。抽拉速度和热区温度影响定向再结晶过程中柱状晶吞并其前端一次再结晶晶粒的速度,从而影响定向再结晶组织;当热区移动的速度、柱状晶吞并前端一次再结晶晶粒的速度和柱状晶前端生成一次再结晶晶粒的速度三者达到平衡时柱状晶界面持续向前推进,最终生成大长径比的柱状晶组织。According to an orthogonal experiment design,the directional recrystallization of hotrolled Cu71Al18Mn11 alloy with deformation degree of 75%was carried out at 800,850 and 900℃,by drawing speed of 2,5 and 15μm/s respectively.The effect of process parameters on the directional recrystallization microstructure and superelasticity of the hot-rolled Cu71Al18Mn11 alloy was assessed,meanwhile,the directional recrystallization mechanism was analyzed.The results show that the direction al recrystallization effect may firstly increase and then decrease with the increase of drawing speed.When the drawing speed is 2μm/s,a small number of columnar grains emerged within the coarse equiaxed grains.When the drawing speed increases to 5μm/s,the microstructure of columnar grains with large aspect ratio can be obtained.However,when the drawing speed further increases to 15μm/s,the directional recrystallization microstructure is a mixture of columnar grains and equiaxed grains.The superelastic properties are better of the directionally recrystallized alloys with columnar grains of large aspect ratio.After being subjected to an applied strain of 12%,the alloy directionally recrystallized at 900℃-5μm/s presents a residual strain of only 1.1%,while a superelastic strain of 9.05%.The drawing velocity and hot zone temperature can affect the speed,at which the columnar grains swallowed up the primary recrystallized grains ahead in the process of directional recrystallization,thus affecting the microstructure of directionally recrystallized alloy.Once,the three speeds,i.e.the hot zone movement,the columnar grains swallowing up the primary recrystallized grains ahead and the generation of new primary recrystallization grains,all are in equilibrium,the front boundary of the existing columnar grains will continues to move forward,which will eventually promote the formation of microstructure of columnar grains with large aspect ratio.

关 键 词：金属材料 Cu-Al-Mn 定向再结晶 超弹性性能 二次再结晶 

分 类 号：TG146.1[一般工业技术—材料科学与工程]