Inconel625合金激光熔覆过程中显微组织演变的数值模拟

Numerical Simulation of Microstructure Evolution of Inconel625 Alloy During Laser Cladding

基于MATLAB模拟平台并结合晶粒的形核与生长理论,采用元胞自动机-有限差分方法构建了Inconel625合金激光熔覆层显微组织演变的数值计算模型,利用该模型对单道激光熔覆过程中合金的显微组织演变进行了模拟,并进行了试验验证,同时研究了激光热输入和异质形核数量对熔覆层晶粒形貌的影响。结果表明:采用建立的模型模拟得到熔覆层内部由柱状晶以及分布在柱状晶之间的亚晶粒组成,靠近熔合线区域由胞状晶组成,与试验结果相吻合;模拟和试验得到柱状晶的平均宽度分别为2.817,2.743μm,相对误差仅为2.69%,验证了计算模型的可靠性;随着激光热输入的减小或异质形核数量的增大,熔覆层组织逐渐细化,晶粒数量增多,柱状晶宽度减小。

On the basis of the MATLAB simulation platform and the grain nucleation and growth theory,the numerical calculation model of microstructure evolution of laser cladding layer of Inconel625alloy was constructed by cellular antomata-finite difference method.The microstructure evolution of the alloy during single pass laser cladding was simulated by the model and verified by experiments.The effects of laser heat input and heterogeneous nucleation quantity on the grain morphology of the cladding layer were studied.The results show that according to the established model simulation,the inner part of the cladding layer was composed of columnar crystals and subgrains distributed between columnar crystals,and the cladding layer near the fusion line consisted of cellular crystals;the simulation was consistent with the test results.The average size of columnar crystals obtained by simulationandtestwere2.817,2.743μm,respectively,and the relative error was only2.69%,which verified the reliability of the calculation model.With decreasing laser heat input or increasing heterogeneous nucleation quantity,the microstructure of the cladding layer was gradually refined,the number of grains increased,and the size of the columnar crystals decreased.