扫描路径对电子束选区熔化TC4成形件性能影响的数值模拟  

Numerical simulation of effects of scanning path on electron beam selective melting process of Ti-6Al-4V

作　　者：齐海波[1,2] 杨明辉[1] 齐芳娟[1] 

机构地区：[1]石家庄铁道学院材料科学与工程分院,石家庄050043 [2]清华大学机械工程系,北京100084

出　　处：《焊接学报》2009年第8期5-8,共4页Transactions of The China Welding Institution

基　　金：中国博士后科学基金资助项目(20070420331);国家自然科学基金资助项目(200475015)

摘　　要：针对电子束选区熔化成形技术中扫描路径对成形件温度分布的影响,建立了模拟实际工况的有限元模型,并按照加载顺序对旋转成形件进行了单元排序.试验发现,长边、短边及分区扫描下起始边起点和终点均存在较大的温度梯度,旋转扫描不仅能有效降低起始点温度下降程度,而且终点还存在正的温度梯度,避免了起始边温度迅速下降;成形件旋转与反向扫描相结合较大地改善了成形件内部的温度分布均匀程度,降低了成形件由于热应力而产生的翘曲变形.结果表明,采用优化得到的扫描方式成形了TC4钛合金拉伸试块,水平方向抗拉强度为1080MPa.Aimed at the influence of temperature distribution on forming parts caused by scanning paths of filling line of electron beam selective melting technology,finite element mode with actual conditions was established and elements belonging to the rotated part were arranged in accordance with the loading sequence.Simulation results show that comparing with long-side scanning,short-side scanning and sub-area scanning,the rotated scanning of rectangular part can greatly decrease temperature gradient in the begin point and the end point of the first scanning line,especially there is a positive temperature gradient in the end point which can avoid the temperature decreasing of the molten metal.Combining rotated scanning with reversing scanning,the uniformity degree of temperature in rectangular part has greatly improved and the curl distortion caused by thermal stress has also decreased.The horizontal tensile strength of the Ti-6Al-4V tensile specimens prepared by the above optimized scanning method is 1 080 MPa.

关 键 词：电子束选区熔化成形 扫描路径 数值模拟 旋转扫描 反向扫描 

分 类 号：TH164[机械工程—机械制造及自动化]