TC4钛合金焊后热处理的数值模拟及组织分析
Numerical simulation and microstructure analysis of post-weld heat treatment for TC4 titanium alloy
谢本昌 1刘馨宇 1张乐 1陈彦孜 1岑耀东 1陈林1
作者信息
- 1. 内蒙古科技大学材料与冶金学院(稀土学院),内蒙古 包头 014010
- 折叠
摘要
使用Ansys软件模拟TC4钛合金焊接及焊后热处理(PWHT)过程,并对焊态及热处理态组织及残余应力变化进行分析.结果表明,焊接过程中各层焊缝由于热输入不同,其温度也不同,其中第1层焊的峰值温度最低(2183.6 ℃),第5层最高(2337.8 ℃),由于各层经历了不同特征的热循环,焊缝区各层马氏体尺寸由19.5 μm向96.2 μm变化.焊后焊缝区主要由αm相+少量β相+部分αt相+析出αg相组成.经PWHT后,接头部分αm相转变为次生(α+β)相,并由XRD图谱观察到(0002)α衍射峰发生"峰分裂",在2θ=39.6°处观察到新峰(110)β,同时峰半高宽降低5.56％～43.75％,表明TC4钛合金的结晶度随着残余应力的消除而得到改善.焊后残余应力主要集中在焊缝附近,此为易断裂位置.垂直焊接方向的残余应力呈对称分布,与温度场分布规律基本相同,经PWHT后各项残余应力均降低.
Abstract
Ansys software was used to simulate the welding and post-weld heat treatment(PWHT)process of the TC4 titanium alloy,and the changes of microstructure and residual stress of the welded and heat treated alloy were analyzed.The results show that during the welding process,the temperature of each layer of the weld varies due to different heat inputs.The peak temperature of the first layer weld is the lowest(2183.6 ℃),and the fifth layer is the highest(2337.8℃).Due to the different characteristics of thermal cycles experienced by each layer,the size of martensite in each layer of the weld zone changes from 19.5 μm to 96.2 μm.The weld zone after welding is mainly composed of αm phase,a small amount of β phase,some αt phase and precipitatedαgphase.After the PWHT,the αm phase in the joint transforms into a secondary(α+β)phase,and it is XRD observed that the(0002)α diffraction peak undergoes peak splitting,a new peak(110)β appears at 2θ=39.6°,the full width at half maximum decreases by 5.56％-43.75％,indicating that the crystallinity of TC4 titanium alloy is improved with the elimination of residual stress.The residual stress after welding is mainly concentrated near the weld seam,which is a fracture prone location.The residual stress along the direction perpendicular to welding is symmetrically distributed,which is basically the same as the distribution of temperature field.After the PWHT,all the residual stresses are reduced.
关键词
TC4钛合金/数值模拟/钨极氩弧焊/焊后热处理/显微组织Key words
TC4 titanium alloy/numerical simulation/TIG welding/post-weld heat treatment/microstructure引用本文复制引用
出版年
2024
NETL
NSTL
万方数据