B30铜镍合金的高温热变形行为及加工图

Hot deformation behavior and processing map of B30 copper-nickel alloy

在变形温度为750~1000℃、应变速率为0.01~10 s^(-1)条件下,对铸态BFe30-1-1铜镍合金进行了热压缩实验。综合分析摩擦和温升对合金流变应力的影响,利用修正后的流变应力曲线构建了BFe30-1-1铜镍合金的Arrhenius双曲正弦函数本构关系模型,基于动态材料模型构建合金的热加工图,研究合金热变形过程中的组织演变规律。结果表明:合金的峰值流变应力随着变形温度的降低或应变速率的增加而升高,摩擦和温升能够显著影响合金的真应力-真应变曲线,热变形过程中发生了动态再结晶,本研究构建的合金本构关系模型对峰值应力的预测值与修正后实验值的平均相对误差仅为3.77%,能够准确地预测合金在不同热变形条件下的流变应力。结合热加工图和微观组织分析,合金的较合理的热塑性变形工艺区间为变形温度900~1000℃、应变速率0.04~0.16 s^(-1),在该变形条件下热压缩后的样品可获得更多的动态再结晶组织。

Hot deformation behavior of as-cast BFe30-1-1 alloy was systematically investigated at the temperature of 750-1000℃and the strain rate of 0.01-10 s^(-1).The effects of friction and adiabatic on the flow stress were analyzed.The stain-stress curves caused by frictional and adiabatic effects were corrected.The corrected curves were used to establish the Arrhenius constitutive equation,so as to the processing map of as-cast BFe30-1-1 alloy on the basis of dynamic material model.The microstructure evolution of alloy during hot deformation was investigated,which shows that the flow-stress increases with the decrease of deformation temperature and the increase of strain rate.Friction and temperature rise can influence the flow stress curves of alloys.The dynamic recrystallization occurs during the hot deformation.The average relative error between the predicted value and the experimental value of peak stress is less than 3.77%.It shows that the constitutive equation can accurately predict the flow stress of different hot deformation conditions.According to the hot processing map and microstructural analysis,the reasonable range of thermoplastic deformation process for BFe30-1-1 copper-nickel alloy is the deformation temperature of 900-1000℃and the strain rate of 0.04-0.16 s^(-1).And more dynamic recrystallization grains of the alloy can be obtained at this deformation condition.