时效处理对镍基单晶高温合金显微组织和硬度的影响

Effect of aging treatment on microstructure and hardness of Ni-based single crystal superalloy

针对不同γ′相体积分数(30%和60%)、经不同时间时效后(0、100、500和1000 h)的镍基单晶高温合金,利用X射线衍射仪(XRD)、扫描电镜(SEM)、原子力显微镜(AFM),并结合纳米压痕试验研究了时效处理对镍基单晶高温合金微观结构和硬度的影响。结果表明,随着时效时间的增加,合金γ′相尺寸逐渐增大。γ′相体积分数为30%和60%的合金中γ′相的形态分别为球形和立方形,γ′相的形态并未随着时效时间增加而发生明显变化;同时,由于60%γ′相体积分数的合金难熔元素含量较高,在时效处理过程中产生了TCP相。时效后,两种沉淀体积分数的合金都呈现出显著的硬化效应,分析认为γ′相强化机制未发生转变。合金在压痕周围的堆积高度随着时效处理时间的增加逐渐增高,而堆积影响的范围逐渐减小。

For Ni-based single crystal superalloy aged for different time(0,100,500,1000 h)with different volume fractions ofγ′phase(30%and 60%),the effect of aging treatment on microstructure and hardness of the tested alloy was studied by X-ray diffraction(XRD),scanning electron microscope(SEM),atomic force microscope(AFM)and nanoindentation experiment.The results show that with the increase of aging time,the size ofγ′phase gradually increases.The morphologies of precipitates in the specimen with theγ′phase volume fraction of 30%and 60%are spherical and cubic shape,respectively,and the morphologies ofγ′phase do not change significantly with the aging time.At the same time,due to the high content of refractory elements in the alloy withγ′phase volume fraction of 60%,the TCP phase is produced during aging treatment.After aging treatment,the specimens with differentγ′phase volume fractions show a significant hardening effect,and the analysis indicates that the mechanism ofγ′phase strengthening is not changed.The height of the material pile-up around the indentation increases gradually with the increase of aging time,while the pile-up effected range decreases gradually.