基于响应面法的Ti_(2)AlNb基合金变形工艺参数优化研究

Optimizationof Deformation Process Parameters of Ti_(2)AlNb-Based Alloys Based on Response Surface Methodology

采用Gleeble-3500热模拟试验机对Ti_(2)AlNb基合金进行了变形温度为650~850℃、应变速率0.001~1 s^(-1)的压缩实验,研究其热变形行为,基于响应面法分析、获得Ti_(2)AlNb基合金最优变形工艺参数范围。首先分析Ti_(2)AlNb基合金的流变应力曲线,并计算热变形激活能Q、ln Z和功率耗散因子η,从而建立不同变形工艺参数下热变形激活能Q、ln Z和功率耗散因子η的二阶响应面模型,再通过多目标可视化优化得出Ti_(2)AlNb基合金优化后的最佳变形工艺参数区域,并结合微观组织验证。结果表明,Ti_(2)AlNb基合金随变形温度升高和应变速率减小流变应力随之减少;建立的响应面模型具有较高精度,可以用于工艺参数的优化与分析;多目标可视化优化结果得出Ti_(2)AlNb基合金优化后的最佳变形工艺参数区域是变形温度750~850℃、应变速率0.005~0.03 s^(-1)。

In this paper,the hot deformation behavior of Ti_(2)AlNb-based alloy was studied byGleeble-3500 thermal simulation experiment machine underdeformation temperaturesof 650-850℃ and strain ratesof 0.001-1s^(-1),and the optimal deformation process parametersrange of Ti_(2)AlNb-based alloy was obtainedby responsesurface method.First,the flow stress curvesof Ti_(2)AlNb-based alloy under different deformation conditions were analyzed,and the hot deformation activation energy Q,lnZand power dissipation factor η were calculated,so as to establish the second order response surface modelforthe thermal deformation activation energy Q,lnZand power dissipation factorη,,and the optimal process parameters region optimization was obtained through multi-objective visual optimization,which was verified bythe microstructure.The results show that the flow stress of Ti_(2)AlNb-based alloy decreases with the increasing in deformation temperature andthedecreasing in strain rate.The established response surface modelshavehigh accuracy,which can be used for optimization and analysis of process parameters.The result of multi-objective visual optimization show that the optimal process parametersregion forTi_(2)AlNb-based alloy is 750-850℃ and the strain rate of 0.005-0.03s^(-1).