选区激光熔化成形Hastelloy X合金有限元模拟及组织性能的各向异性

Finite Element Simulation and Anisotropy of Microstructure and Properties for Selective Laser Melting Formed Hastelloy X Alloy

基于选区激光熔化(SLM)制备HastelloyX合金的成形原理,通过Fortran语言编写DLUX子程序加载高斯光源,采用有限元分析软件ABAQUS对有限元模型的瞬态温度场和冷却速度进行数值模拟,并用实验对分析结果进行验证。研究了粉末颗粒与高斯光源在成形时的热传递、熔化、金属液流动及凝固过程。结果表明:HastelloyX合金的微观组织中纵截面呈现鱼鳞状等轴晶,横截面呈现羽毛状柱状晶。SLM成形产生了很大的温度梯度,是一个高冷却速度非平衡动态过程,平均冷速为3.02×10^(6)℃/s。在高冷速、细晶强化作用下,纵/横截面的抗拉强度分别达到了锻造的97%和89%,屈服强度达到了锻造产品的99%和94%,纵截面呈现高强塑匹配性能,满足了工业行业标准需求。

Based on the forming principle of Hastelloy X alloy prepared by selective laser melting(SLM), the DLUX subroutine was written in Fortran language to load Gaussian light source, and finite element analysis software ABAQUS was used to numerically simulate the transient temperature field and cooling rate of finite element model, and the analysis results were verified by experiments. The heat transfer, melting, liquid metal flow and solidification process of powder particles and Gaussian light source during forming were studied. The results show that the microstructure of Hastelloy X alloy presents equiaxed crystal with fish scales in vertical section and feathery columnar crystal in cross section. SLM forming produces a large temperature gradient, which is a non-equilibrium dynamic process with high cooling rate. The average cooling rate is 3.02×10^(6) ℃/s. Under the effects of high cooling rate and fine grain strengthening, the tensile strength of vertical and cross sections reach 97% and 89% of that of forging, the yield strength reach 99% and 94% of that of forging product, respectively. The vertical section shows high strength-plastic matching performance, meeting the requirements of industry standards.