钛合金二层板结构超塑成形/扩散连接试验研究  

Process of Superplastic Forming/Diffusion Bonding for Two-Sheet Structure of Titanium Alloy

作　　者：杨钦鑫 童国权[1] 何泽洲 Yang Qinxin;Tong Guoquan;He Zezhou(College of Mechanical and Electronic Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)

机构地区：[1]南京航空航天大学机电学院,江苏南京210016

出　　处：《稀有金属》2017年第12期1305-1310,共6页Chinese Journal of Rare Metals

基　　金：江苏省"六大人才高峰"资助项目(2014ZBZZ003)资助

摘　　要：采用超塑成形/扩散连接(SPF/DB)工艺对TC4钛合金二层板结构进行制备。对TC4钛合金试样进行超塑拉伸试验研究,确定了温度900℃和应变速率9.8×10^(-4)s^(-1)为最佳超塑成形的工艺参数,并计算得出本构方程中的应变速率敏感指数m=0.57,K=998.5。利用MSC.MARC软件对试验件的成形过程进行有限元模拟分析,获得了优化的压力-时间加载曲线。模拟结果显示板料在拐点圆角处最薄,且最大减薄率为42.5%,最大成形气压为2.0 MPa;在T=900℃和6)ε=9.8×10^(-4)s^(-1)下,加载优化的压力-时间曲线,成功进行了TC4二层板结构SPF/DB成形试验。最后对试验件进行了表面质量检查和扩散连接位置显微组织观察分析,结果显示:钛合金二层板的试验件的整体成形效果良好,试验件表面没有出现凹坑缺陷的现象,加强筋超塑成形完全;扩散连接情况良好,界面无明显缺陷,连接处实现了可靠的冶金连接。证明了所述工艺方案成形二层板结构件的可行性。The process of superplastic forming and diffusion bonding （SPF/DB） for two-sheet structure of Ti-6Al-4V titanium alloy was performed. The temperature of 900 ℃ and the strain rate of 9.8 ×10-4 s- 1 were determined as the best forming process parmneters in superplastic tensile test of Ti-6Al-4V titanium alloy. The strain rate sensitivity exponent of 0.57 and K = 998.5 were calculated ac- cording to constitutive equation. The SPF process was simulated by using finite element software MSC. MARC to optimize the curve of pressure-time. The finite element method （FEM） results showed that the thinnest place of the face sheet was located at the rounded corners and the maximum reduction ratio of sheet was 42.5% , and the largest pressure of SPF was 2.0 MPa. The test was conducted successfully by using the optimized pressure load curves at the temperature of 900 ℃ and strain rate of 9.8 × 10 -4 s-1. The surface quality of the formed product was inspected and the mierostrueture of the diffusion bonding interface was analyzed. The results showed that the forming of two-sheet structure had good quality, and the surface had no defects of pit, thus reinforcing of SPF completed. The connection joint interface of enhancement plate with sheet metal had no obvious defects, and joint had also realized the reliable metal- lurgical connection. Tile results proved the forming feasibility of two-sheet structure by using the described process.

关 键 词：TC4钛合金 双层板结构 超塑成形/扩散连接 有限元分析 

分 类 号：TG146.23[一般工业技术—材料科学与工程]