GH79合金高温变形行为及变形机理研究

Elevated Temperature Compression Deformation Behavior and Mechanism of GH79 Superalloy

摘要:

利用Gleeble-3800热压缩模拟试验机,对GH79合金高温热变形行为及变形机理进行了系统的研究。以高温压缩实验为基础,以高温压缩过程的力学行为特征及微观组织演变规律为主线,获得了该合金在不同应变速率、不同变形温度下的应变速率敏感性指数m值、变形激活能Q值、晶粒指数p值的变化规律。分别构建了不同失稳判据下的动态DMM热加工图及包含位错数量的变形机理图。应用热加工图理论分析了该合金的适合成形加工区和流变失稳区,运用变形机理图预测了该合金高温变形过程基于柏氏矢量补偿的晶粒尺寸、模量补偿的流变应力下的位错演变规律及高温变形机理。

Abstract:

The hot compression deformation of GH79 superalloy were investigated systematically on a Gleeble-3800 thermal simulating tester. Based on the hot compression test behavior and mechanism on high temperature deformation behavior and microstructure evolution, the variation of strain rate sensitivity exponent m, activation energy Q and grain size exponent P values at different strain rates and different temperatures were obtained. The dynamic DMM hot processing map based on different instability criteria was drawn while the deformation mechanism maps incorporating dislocations the inside grains were obtained. The processing map was used to analyze the processing instability regime and appropriate processing regime. With the deformation mechanism maps, the Burgers vector compensated grain size, the dislocation evolution rule at modulus compensated flow stress and the modulus compensated stress and the dislocation quantities of GH79 superalloy at different temperatures, the hot deformation mechanisms were elucidated.