材料科学
高温合金
动态再结晶
应变率
软化
消散
流动应力
变形(气象学)
复合材料
加工硬化
硬化(计算)
热加工
压力(语言学)
大气温度范围
冶金
热力学
微观结构
物理
语言学
哲学
图层(电子)
作者
Xiaomin Chen,Meng-Tao Ning,Hongwei Hu,Yongcheng Lin,Xiaojie Zhou,Jian Zhang,Xianzheng Lu,Jian Chen,Yanxing Liu
标识
DOI:10.1016/j.matchar.2023.112916
摘要
The hot compressive behavior of GH4698 superalloy is examined in the temperature range of 950–1100 °C and strain rate range of 0.001–1 s−1. The observations from the flow stress curves reveal work hardening and dynamic recovery features at the beginning of the deformation, which leads to rapid increase in the true stress. After the true stress exceeds its peak level, the dynamic softening induced by dynamic recrystallization (DRX) becomes dominant, and the true stress gradually drops until a relatively stable stress level. Considering the coupled impact of temperature and strain rate, an improved Zhu-Ou-Popov (ZOP) model is proposed to characterize the hot deformation behavior of the tested superalloy. The results verify the accuracy of the improved ZOP model for reproducing the hot deformation behavior of the tested superalloy with a correlation coefficient as high as 0.9721. Additionally, the processing maps are established according to the dynamic material model. Furthermore, the microstructural evolution is examined to validate the feasibility of the established processing maps. The results reveal that the processing maps can be decomposed into three domains: an unstable region, a stable region with low power dissipation, and a stable region with high power dissipation. The main instability regions are 950–1050 °C, 0.04–1 s−1 and 1095–1100 °C, 0.1–0.22 s−1, where obvious microcracks and mixed grains can be observed. The stable zone with low power dissipation consists of three parts: 1040–1100 °C, 0.1–1 s−1, 1040–1100 °C, 0.02–0.1 s−1; 950–1065 °C, 0.001–0.04 s−1. In these regions, the primary elongated grains and small DRX grains are the predominant microstructures. The stable region with high power dissipation is observed at 1010–1100 °C and 0.001–0.1 s−1, where the DRX grains are found to be fine and uniform, and it is the optimal hot working window to achieve the desired performance of the tested superalloy.
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