K4104镍基高温合金表面Al及Al-Si渗层的微观组织研究

Research on the microstructure of Al and Al-Si coatings on K4104 nickel-based superalloy

分别采用料浆法和粉末包埋法在K4104镍基高温合金上制备Al-Si和Al渗层。借助X射线衍射(XRD)和电子探针(EPMA),详细分析Al-Si、Al渗层的微观组织,探讨渗层形成机理,并且对比研究Al-Si共渗层和单渗Al层的微观结构,找出Si对渗Al层组织结构的影响。结果表明:Al-Si共渗渗层中包含CrxSiy化合物、富Al的β、富Ni的β、Cr的碳化物和γ′相,单渗Al层则包含富Al的β、富Ni的β、Cr的碳化物和γ′相;Si的加入使Al-Si共渗层出现过渡层,过渡层导致Al元素含量由外向内的减少趋势较单渗Al的平缓。

The Al-Si diffused and aluminized coatings were prepared on a nickel-based superalloy K4104 by slurry aluminizing and pack cementation, respectively. The microstructure of Al-Si coating and aluminized coating was analyzed by means of X-ray diffraction (XRD), electron probe microanalysis (EPMA), and the formation mechanism of Al-Si and aluminized coatings was also discussed. The microstructure of Al-Si coating was compared with that of aluminized coating in order to find out the effects of Si. The results show that the Al-Si coating consists of CrxSiy, Al-rich β, Ni-rich β, Cr-rich and γ'. The aluminized coating consists of Al-richβ, Ni-rich β, Cr-rich and γ'. Owing to the effect of Si, there is transition layer in Al-Si coating the declining trend of the aluminum concentration in the coating layer is smoother than that of the aluminized coating.