基于快速铸造的钛合金数值模拟及组织性能

Numerical Simulation and Microstructure and Performance of Titanium Alloy Based on Rapid Casting

利用选区激光烧结(SLS)技术,建立ZTC4合金熔模铸造试验模型,通过ProCAST软件对其温度场和凝固过程进行分析,结合CAF模块对晶粒生长结构进行研究,同时研究了合金的微观组织及力学性能。结果表明,采用底注式浇注系统时,合金液从外向内顺序凝固,没有夹渣卷入缺陷。试样底部的冷却速率>顶部冷却速率,平均冷却速率为1.26℃/s,组织中存在魏氏组织,底部晶粒尺寸小于顶部,试样平均屈服强度和抗拉强度分别为785.67MPa、937.55MPa,伸长率和断面收缩率分别为14.83%和19.33%,综合性能满足标准要求。

Based on the principle of rapid casting and selective laser sintering(SLS)technology,an investment casting test model of ZTC4alloy was established.The temperature field and solidification process were analyzed by the ProCAST finite element analysis software,and the grain structure and grain growth were analyzed by CAFmodule.Meanwhile,the microstructure was characterized and mechanical properties were measured by SEM,EDS and tensile testing.The results reveal that adopting the bottom gating system with vacuum pouring,the solidification sequence presents from outside to inside without slag inclusion defect inside.The cooling rate at the top of the sample is lower than that at the bottom,and the average cooling rate is 1.26℃/s.Widmanstatten structure mainly composed of whiteαphase,blackβlamellae andαphase at the grain boundary is distributed at the micro level.Larger grain size affects the mechanical properties,presenting high strength and low plasticity.The average yield strength and tensile strength of the alloy reach 785.67MPa and 937.55MPa,respectively,and the elongation and section shrinkage rate are 14.83%and 19.33%,respectively.The comprehensive properties meet the requirements of GB/T 6614-2014national standard for titanium and titanium alloy castings and industrial production.