基于热变形图方法的GH4706合金微观组织均匀化控制

Microstructure Homogenization Control of GH4706 Alloy by Hot Deformation Maps

摘要:

GH4706合金在950~1150 ℃的温度范围内和0.001~1 s^-1的应变率范围内，在1.2的真应变下进行了热压缩试验。使用动态再结晶分数、平均晶粒尺寸和晶粒分布标准偏差的云图确定了最佳热变形温度和应变率范围。基于流动应力曲线绘制了0.4~0.9真应变下的加工图，以确定在不同温度和应变率下最佳微观组织均匀化效率相对应的应变。结果表明：在最佳参数范围内，在1150 ℃和0.01 s^-1条件下，约为0.6的真应变具有最高的微观组织均匀化效率。实验获得的晶粒取向扩展图证明了此结论。本研究为GH4706合金的微观组织均匀化控制提供了一种有效的方法，为确定工程中锻件局部最小应变阈值提供了有效参考。

Abstract:

Hot compression tests for GH4706 alloy were performed at a true strain of 1.2 within the temperature range of 950–1150 °C and the strain rate range of 0.001–1 s^-1. The optimal hot deformation temperature and strain rate range were determined using nephogram maps of dynamic recrystallization fraction, average grain size, and grain distribution standard deviation. Processing maps at true strains from 0.4 to 0.9 were generated based on flow stress curves to identify the strain corresponding to optimal microstructure homogenization efficiency at various temperatures and strain rates. Results show that within the optimal parameter range, under the conditions of 1150 °C and 0.01 s^-1, the true strain of about 0.6 results in the optimal microstructure homogenization efficiency. The grain orientation spread maps obtained from the experiment also confirms this conclusion. This study provides an effective method for microstructure homogenization control of GH4706 alloy and an effective reference for the minimum strain threshold of the local part of the forging in engineering.