热处理对K403镍基高温合金组织和性能的影响

Effect of Heat Treatment on the Microstructure and Properties of Alloy K403

采用光学显微镜、扫描电镜对K403镍基高温合金的铸态组织和不同固溶和时效处理后的组织进行了观察,研究了不同固溶和时效处理对K403合金组织、抗拉强度、硬度的影响。结果表明,合金经过1140,1180℃不完全固溶处理后,组织为大小2种尺寸的γ’相;经过1210℃完全固溶处理后空冷,均匀析出0.2μm的γ’相。时效后,合金抗拉强度和硬度得到提高。经1190℃,4h,AC+940℃,16h,AC处理,合金获得最佳的抗拉强度和硬度。经1190℃,4h,AC+980℃,16h,AC处理,γ’相长大到0.6μm,导致合金硬度相对下降。

The microstructure features, tensile and hardness properties of K403 superalloy at as-cast, as-solution and as-aged conditions were investigated using optical microscopy and scanning electron microscopy in detail. The results show that the γ’ precipitates with two sizes were obtained after uncompleted solid solution at 1140 ℃ and 1180 ℃ for 4 h. Uniform cubical γ’ precipitates about 0.2 μm in size were obtained after completed solid-solution at 1210 ℃ for 4 h and air cooling. The tensile properties and room temperature hardness of the alloy are obviously improved after aging. Compared with other heat treatments, the alloy yields the best tensile properties and hardness after treatments of 1190 ℃, 4 h,air cooling ＋ 940 ℃, 16 h, and air cooling. When aging at 980 ℃ for 16 h, the γ’ phase became coarser （0.3～0.6 μm）, resulting in the decrease of properties and hardness.