GH4698合金的热处理

Heat treatment of GH4698 alloy

针对GH4698合金提出了一种新的热处理工艺:再结晶退火+标准热处理制度,即:980℃×4 h空冷+1100℃×8 h空冷+1000℃×4 h空冷+775℃×16 h空冷+700℃×16 h空冷。通过观察显微组织并测试合金的残余应力,研究了再结晶退火对组织和性能的影响。结果表明,再结晶退火能够有效改善合金的微观组织不均匀性,释放合金内部残余应力,降低后续热处理过程中的晶粒异常长大,从而显著提高GH4698合金的高温力学性能,且保持室温力学性能不变。

A novel heat treatment of GH4698 alloy was put forward that is recrystallization annealing + conventional heat treatment,i. e.980 ℃ × 4 h with air cooling( AC) + 1100 ℃ × 8 h( AC) + 1000 ℃ × 4 h( AC) + 775 ℃ × 16 h( AC) + 700 ℃ × 16 h( AC). Effects of recrystallization annealing on microstructure and mechanical properties of the GH4698 alloy were investigated by microstructure observation and residual stress measurement. The results show that the recrystallization annealing can effectively improve non-uniform microstructure,release residual stress and reduce abnormal grain growth during subsequent heat treatment. As a result,the high temperature mechanical properties of GH4698 alloy are remarkably enhanced and the room temperature mechanical properties can be kept at the same level.