超固相线液相烧结GH4049粉末合金

Supersolidus liquid phase sintering of GH4049 powder alloy

采用超固相线液相烧结方法制备了GH4049粉末合金,研究了合金的致密化机理、热处理对合金组织和力学性能的影响以及Y2O3对合金的强化作用。结果表明:在1350℃真空烧结120min可以制备出相对密度为99·2%的GH4049粉末合金,合金的烧结致密化机理为颗粒重排与粘性流动。经热处理后,GH4049粉末合金的抗拉强度、屈服强度和伸长率分别为1113MPa、760MPa和13%,接近变形GH4049合金;晶内析出了约200nm的方形大γ′相和40nm左右的球形γ′相,平均晶粒大小在80μm以下。加入质量分数为0·05%的纳米级Y2O3后,改善了合金的抗应力松弛性能。

Nickel base powder superalloy GH4049 was prepared from pre - alloyed powder by supersolidus liquid phase sintering. The mechanism of densification and effects of heat treatment on microstructure and mechanical properties and the reinforcing action of addition of Y2O3 nano - particles were studied. The results show that the compacts with relative density over 99% can be obtained by sintering at 1 350 ℃ for 120 min in vacuum. The densification mechanism is particle rearrangement and viscous flow. The tensile strength and yield strength and ductility are 1 113 MPa and 760 MPa and 13% respectively,which are near that of wrought alloy GH4049. There are two kinds of γ＇ phase precipitated in the grains. The rectangular γ＇ phase is about 200 nm and the global γ＇ phase is about 40 nm. The average grain size of matrix is below 80 μm. Addition of Y2O3 about 0.05wt% can improve the alloy stress relaxation property.