GH4169合金的反常应力松弛行为

Abnormal Stress Relaxation Behavior of GH4169 Alloy

摘要: 对GH4169合金在500，620，720℃下进行了应力松弛、蠕变和热膨胀试验，结合显微组织观察研究了合金的应力松弛行为。结果表明：在500℃和620℃应力松弛试验过程中，GH4169合金的应力随时间的延长反常增大，在蠕变过程中表现为负蠕变应变，而在720℃下合金的应力松弛和蠕变行为均正常；在不同温度热膨胀试验过程中，GH4169合金均出现了收缩现象；γ″相析出使得γ基体的晶格常数减小，是导致GH4169合金在620℃下应力反常增大的主要原因。

Abstract: Stress relaxation, creep and thermal expansion tests at 500, 620, 720℃ were conducted on GH4169 alloy, and then the stress relaxation behavior was studied by combination of microstructure observation. The results show that the stresses in the GH4169 alloy increased abnormalloy with increasing time during stress relaxation tests at 500℃ and 620℃, and showed negative creep strains during creep. However, the stress relaxation behavior and creep behavior of the alloy were normal at 720℃. Shrinkage was observed in the GH4169 alloy during thermal expansion tests at different temperatures. The reduction of lattice parameter of γ matrix, which was caused by the precipitation of γ″ phase, was the main reason for the abnormal increase of stresses in the GH4169 alloy at 620℃.