一种新型镍基粉末高温合金等温热压缩过程中的超塑性变形行为研究

Superplastic Deformation Behavior of Nickel-Based Powder Superalloy During Isothermal Hot Compression

基于Gleeble等温热压缩试验,并结合OM、SEM、EBSD等分析手段,研究了一种新型热挤压态第3代镍基粉末高温合金FGH4113A(WZ-A3)在超塑性压缩变形过程中的流动特性和微观组织演化规律。给出了在温度1050、1100℃,应变速率0.001、0.005 s^(-1),不同变形量(应变)条件下的超塑性变形行为及其变形机制。结果表明:FGH4113A(WZ-A3)合金在热压缩变形过程中表现出良好的超塑性,未发现孔洞或裂纹;1100℃/0.001 s-1大变形后期(60%~80%变形量)晶粒有长大趋势,其余变形条件晶粒尺寸变化不大;在超塑性压缩变形过程中,累积的位错主要通过动态回复和动态再结晶所湮灭,晶界滑移是发生大变形而未开裂的主要原因。该研究结果为新型的FGH4113A(WZ-A3)合金超塑性等温锻造工艺制定奠定了良好的基础。

Based on Gleeble isothermal hot compression test,the flow characteristics and microstructure evolution of a new hot extruded third generation nickel-base powder superalloy FGH4113A(WZ-A3) during superplastic compression deformation was studied by OM,SEM and EBSD analysis methods.The superplastic deformation behavior and deformation mechanism at different temperatures of 1050and 1100 ℃,different strain rates of 0.001 and 0.005 s^(-1),and different amount of deformation(strain) were presented.The results show that FGH4113A(WZ-A3) alloy exhibits good superplasticity during hot compression deformation,and no cavities or cracks are observed.The grain size tends to grow at 1100 ℃/0.001 s^(-1) after large deformation(60%~80% deformation),while grain size has little change under other deformation conditions.In the process of superplastic compression deformation,the accumulated dislocation is annihilated mainly by dynamic recovery and dynamic recrystallization,and grain boundary slip is the main reason for large deformation without cracking.The results lay a good foundation for the development of superplastic isothermal forging process of FGH4113A(WZ-A3) alloy.