基于热压缩的Cu-15Ni-8Sn合金动态再结晶行为研究

Dynamic Recrystallization Behavior of Cu-15Ni-8Sn Alloy Based on Hot-Compression Test

目的获得Cu-15Ni-8Sn合金动态再结晶临界模型,描述热变形参数对动态再结晶晶粒尺寸的影响规律。方法基于前期通过Gleeble-3500热模拟机得到的热压缩实验数据,分析Cu-15Ni-8Sn合金在不同热变形参数下的再结晶晶粒尺寸及流变应力数据,采用线性回归拟合等方式建立动态再结晶模型,并利用数值模拟与实验相结合的方法验证模型精确度。结果采用YADA模型描述Cu-15Ni-8Sn合金的动态再结晶,通过线性拟合求得模型参数C_(1)=11895.554,C_(2)=0.1503,C_(3)=0.1553,C_(4)=3.933×10^(−4),C_(5)=2995.6409,数值模拟与实验所得的平均晶粒度分别为16.7μm和15.5μm。结论变形温度和变形速率对Cu-15Ni-8Sn合金热变形中的再结晶过程有重要影响。变形温度越高,临界应变越小,越容易发生动态再结晶,动态再结晶晶粒尺寸越大;应变速率越小,动态再结晶晶粒尺寸越大。研究所构建的Cu-15Ni-8Sn合金动态再结晶临界模型具有较高精度,将为后续该合金热塑性变形工艺设定提供理论基础。

The work aims to establish a dynamic recrystallization critical model for Cu-15Ni-8Sn alloy and study the effect of hot deformation parameters on grain size of dynamic recrystallization.Based on the experimental data of hot-compression tests obtained by Gleeble-3500 thermal analogue machine,recrystallized grain size and flow stress of Cu-15Ni-8Sn alloy under different thermal deformation parameters were analyzed.A dynamic recrystallization model was established by linear regression fitting and other ways.The precision of the model was verified by numerical simulation and experiment.The dynamic recrystallization of Cu-15Ni-8Sn alloy was described with YADA model.Through linear fitting,parameters of the model were obtained to be C_(1)=11895.554,C_(2)=0.1503,C_(3)=0.1553,C_(4)=3.933×10^(−4),C_(5)=2995.6409.The average gain size of numerical simulation and experiment was 16.7μm and 15.5μm respectively.The results show that deformation temperature and strain rate have important effects on the recrystallization of Cu-15Ni-8Sn alloy in thermal deformation.With the increase of deformation temperature,the critical strain decreases gradually,the dynamic recrystallization occurs more likely,and the grain size of dynamic recrystallization increases.Moreover,the smaller the strain rate is,the larger the grain size is.The dynamic recrystallization critical model established for Cu-15Ni-8Sn alloy has high accuracy.The results of this study will provide a theoretical basis and technical reference for thermal plastic forming of Cu-15Ni-8Sn alloy.