倒双级时效对镍基高温合金组织及高温拉伸性能的影响

 研究了固溶+两段时效热处理工艺对镍基高温合金组织及性能的影响。结果表明：镍基高温合金中的γ′相粒子半径大于40 nm时，位错与γ′相的交互作用由切割机制转变为绕过机制，合金强度明显降低；γ′相的长大规律符合Oswald熟化过程规律；合金在第二段时效过程中，晶界碳化物转变成颗粒状，使其塑性显著提高。

Effect of Inverted Two-Stage Aging on Microstructure and Properties of Ni Base Superalloy

The effect of inverted two stage aging on microstructure and properties of a Ni base superalloy has been studied. The results indicate that the critical size of γ′ particles is about 40 nm in which dislocation can pass γ′ phase and the interaction mechanism between dislocation and γ′ particle is transformed from cutting to bypass. Tensile strength decreases rapidly when average radius of γ′ particles is larger than the critical size. The growth of γ′ particles in the second aging stage is suitable for Oswald law. Grain boundary carbide turns into globular morphology at secondary aging stage and tensile plasticity increases simultaneously.