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采用透射电镜(TEM)和扫描电镜(SEM)分析了不同时效热处理制度下镍基GH99高温合金中γ’相的尺寸、形貌变化,采用维氏硬度计测试不同时效热处理制度下的合金硬度。结果表明:γ’相随着时效温度的升高和保温时间的延长而明显粗化,其粗化符合沉淀相粗化理论(LSW理论);随着γ’相的不断长大,部分γ’相的形貌由球形转变为立方形。经计算得到γ’相长大激活能约为248.8 k J/mol。此外发现硬度随γ’相尺寸的增大而逐渐增大,但当γ’相尺寸超过37.2 nm时,硬度随γ’相长大呈下降趋势,在750℃时得到合金的最大硬度为395.16 HV。
The size and morphology of γ ’phase in nickel base GH99 superalloy under different aging treatments were analyzed by transmission electron microscope (TEM) and scanning electron microscope (SEM). The hardness of the alloy under different aging treatments was measured by Vickers hardness tester. The results show that the γ ’phase obviously coarsens as the aging temperature increases and the holding time prolongs, and its coarsening accords with LSW theory. With the continuous growth of γ’ phase, some γ ’ Phase morphology from spherical to cubic. The calculated activation energy of the γ ’phase is about 248.8 kJ / mol. In addition, the hardness increases with the increase of γ ’phase size. However, when the γ’ phase size exceeds 37.2 nm, the hardness decreases with the growth of γ ’phase. The maximum hardness of the alloy obtained at 750 ℃ is 395.16 HV .