Ti2AlNb合金电子束熔透焊的数值模拟  

Numerical Simulation for Full-Penetration Electron Beam Welding of Ti2AlNb Alloy

作　　者：李艳军[1,2,3] 赵玥[1] 吴爱萍[1,2,3] 朱瑞灿[4] 王国庆[5] 

机构地区：[1]清华大学,北京100084 [2]摩擦学国家重点实验室,北京100084 [3]先进成形制造教育部重点实验室,北京100084 [4]首都航天机械公司,北京100076 [5]中国运载火箭技术研究院,北京100076

出　　处：《稀有金属材料与工程》2017年第5期1341-1345,共5页Rare Metal Materials and Engineering

基　　金：先进成形制造全流程建模与仿真创新平台项目(2012 2X04012-011);航天一院高校联合创新基金(CALT201209)

摘　　要：采用热-弹-塑性有限元计算模拟了Ti2AlNb合金电子束焊的温度场和应力场。为了准确反映熔透型电子束焊接的特点,对旋转高斯曲面体热源模型进行了改进。研究结果表明:采用改进的热源模型能准确地模拟穿透型电子束焊焊缝横截面轮廓;残余应力的模拟结果与实验结果吻合较好,证明了有限元模型的正确性;Ti2AlNb合金电子束焊后残余应力以纵向拉应力为主,且集中分布在距焊缝中心线3 mm的区域内;横向残余应力在表面附近区域呈压应力,内部呈拉应力,表面横向压应力是由焊缝纵向和厚度方向的收缩导致的;焊缝内部出现三向拉应力的状态。A 3D thermal elastic-plastic finite element model was developed to predict welding residual stresses induced by full-penetration electron beam welding of Ti2A1Nb alloy. Rotary-Gauss body heat source model was modified to reflect the full-penetration weld. The results show that the cross section profiles of the weld seam simulated with the modified heat source model agree well with the experimental results. The residual stress distribution also has a good agreement between the numerical and experimental results, which proves the validity of the finite element model. The longitudinal tensile stresses plays a major role in the welded joint of Ti2A1Nb alloy and the region of residual stresses distribution is very narrow within a distance 3 mm away from the weld centerline. Compressive transverse stress is observed on the top and bottom surfaces while tensile transverse stress at the center of the weld, and the discrepancy is ascribed to the longitudinal and normal contracting of the weld. In addition, the phenomenon of local three dimensions residual tensile stresses appears in the plate center.

关 键 词：Ti2AlNb合金 电子束焊 残余应力 数值模拟 

分 类 号：TG456.3[金属学及工艺—焊接]