Ti6Al4V合金粉末高温高压成形过程中粉固界面及其耦合变形研究

Research on powder-solid interface and coupling deformation of Ti6Al4V alloy powder during high temperature and high pressure

通过数值模拟和热等静压(HIP)试验,研究Ti6Al4V合金粉末热等静压成形过程中与包套的接触状态,建立热等静压力学模型以及摩擦因数的力学方程,基于数值模拟结果,根据粉末致密化理论就接触模型对摩擦因数、相对密度、相对位移的影响进行分析和讨论。研究结果表明:在热等静压过程中,Shima模型对描述Ti6Al4V合金粉末的致密化过程具有较高精度,圆柱试验件尺寸数值模拟结果与试验结果的相对误差在5%以内;Stick-slip模型对于摩擦因数的变化过程以及相对位移的变化趋势的预测结果与实际一致,摩擦因数稳定值为0.15;Bilinear模型对于相对密度变化趋势的预测结果与实际一致,相对密度误差为1%;采用Stick-slip模型可以准确地预测包套的变形及粉末的致密化过程。

In order to study the contact state of Ti6Al4V alloy during hot isostatic pressing(HIP),numerical simulations and HIP test were carried out.The mechanical model and mechanical equation considering friction coefficient of HIP was proposed.According to the theory of powder densification,the impact of the contact model on friction coefficient,relative density and relative displacement was discussed based on numerical simulation results.The results show that the Shima model describes the densification process of Ti6Al4V alloy powder with high precision.The cylindrical capsule size error between numerical simulation and experiment is less than 5%.The predicted results of Stick-slip model in the variation trend of coefficient friction and relative displacement are consistent with the actual situation.The predicted results of Bilinear model in the changing trend of relative density are consistent with the actual situation.The coefficient of friction is stable at 0.15.The error of relative density between numerical simulation and experiment is only 1%.The Stick-slip model can accurately predict the deformation of the capsule and the densification process of the powder.