热等静压及后续热处理对MIM418涡轮合金组织与性能的影响

Influence of hot isostatic pressing and the subsequent heat treatment on microstructure and properties of MIM418 turbine alloy

比较了热等静压前后MIM418合金组织与致密度的变化,研究了不同淬火(水冷和空冷)、时效工艺对热等静压后固溶态MIM418合金微观组织及各种析出相的影响,利用扫描电镜、透射电镜、能谱分析等手段分析了合金中主要强化相γ'和碳化物二者的形态、大小和分布的规律。结果表明,热等静压可明显提高MIM418合金的致密度,但对显微组织影响不大,"固溶+中温时效"可以获得较好的硬化效果,主要析出强化相γ'和二次碳化物的析出受固溶冷却方式的影响较大,γ'相纳米化和二次碳化物的析出或将有益于MIM418硬度的大幅度提高。

The effect of hot isostatic pressing( HIP) on the density and microstructure of MIM 418 superalloy prepared by metal injection molding( MIM) was investigated,and the effect of the subsequent heat treatment on the microstructure of the MIM 418 superally after HIP was studied. The morphology,size and distribution of the strengthening phase γ' and carbide were analyzed in detail by scanning electron microscopy( SEM) equipped with EDS and transmission electron microscopy( TEM). The results show that the HIP can increase the density of MIM 418 obviously,but has little influence on microstructure. The superior hardening effect can be achieved through the process of solution and medium temperature aging,as cooling speed has a significant impact on the γ' and carbide. Nanocrystallization ofγ'and the uniform distribution of carbide precipitation can be beneficial to the hardness of the MIM418 which can lead to increase in the mechanical performance.