Cu-3.0Ni-0.64Si合金的热变形行为

对Cu-3.0Ni-0.64Si合金进行了变形温度为750~900℃、变形速率为0.001~1s~(-1)条件下的等温压缩实验。结果表明,随着变形温度升高或变形速率降低,峰值应力明显降低,合金容易发生动态再结晶。通过线性回归分析,求得Cu-3.0Ni-0.64Si合金的变形激活能为410.4kJ/mol,建立了Cu-3.0Ni-0.64Si合金的高温热变形流变应力本构方程6)ε=e~(40.56)sinh(0.017σ)]~(5.21)exp-410.4×10~3/(RT)]。分别讨论了变形温度和变形速率对Cu-3.0Ni-0.64Si合金在等温压缩变形中显微组织的影响。最后基于动态材料模型理论,用Prasad失稳判据,得到不同真应变量下的热加工图。优化后的工艺参数为变形温度860~900℃和变形速率0.002~0.01s~(-1)。

Hot Deformation Behavior of Cu-3.0Ni-0.64Si Alloy

The isothermal compression tests of Cu-3 .0Ni-0 .64Si alloy were proceed at 750—900 ℃ with the strain rate of 0.001—1 s-1 .The results showed that the peak stress decreased with the increase of the deformation temperature or the decrease of the strain rate ,and the alloy was prone to dynamic recrystallization .The hot deformation activation energy was 410 .4 kJ/mol and the corresponding thermal deformation constitutive relation equation was ε=e40 .56 sinh(0 .017σ)]5 .21 exp -410 .4 × 103/(RT)] of Cu-3.0Ni-0 .64Si alloy ,which were obtained by the linear regression analysis .The effects of the deformation temperature and strain rate on the microstructure of Cu-3 .0Ni-0 .64Si alloy were discussed .The hot processing maps of different true strain were constructed based on the dynamic material model and Prasad instability criterion .The optimized process parameters were deformation temperature of 860—900 ℃ and strain rate of 0 .002—0 .01 s-1 .