内燃机用IN718镍基合金热变形动态组织性能分析

Analysis on dynamic microstructure properties in hot deformation for nickel base alloy IN718 used in engine

对锻态IN718镍合金在不同工艺参数下进行了热压缩实验。采用OM、SEM和TEM分析方法,研究了不同热变形条件下IN718合金组织的结构变化规律。研究结果表明:IN718合金的流变应力随着应变的增大而增大,是典型的有动态再结晶塑性流变过程。在各个热变形工艺条件下,合金表现出显著的峰值现象,当温度上升或者应变速率变小后都会引起峰值应力的下降。合金在1050℃下生成了许多细小的再结晶晶粒,当热处理温度上升后,合金的平均晶粒尺寸更大。当应变速率增大后,合金晶粒尺寸不断减小。1080℃下以0. 001 s^(-1)应变速率使试样发生塑性变形时,晶粒中的细小γ'相可以对位错运动起到明显的抑制作用。

The hot compression experiments of forged IN718 nickel alloy under different process parameters were carried out,and the microstructures of IN718 alloy under different thermal deformation conditions were analyzed by OM,SEM and TEM.The results show that the rheological stress of IN718 alloy increases with the increasing of strain,which is a typical plastic rheological process with dynamic recrystallization.Under various thermal deformation conditions,the alloy shows a significant peak phenomenon,and the peak stress of alloy decreases when the temperature increases or the strain rate decreases.Furthermore,the alloy grows into many tiny recrystallization grains at 1050℃,and its average grain size gets larger after the heat treatment temperature rises.As the strain rate increases,the grain size decreases continuously.Under 1080℃and strain rate of 0.001 s-1,the plastic deformation of sample occurs,and the smallγ’phase in the grain has obvious inhibitory effect for the dislocation movement.