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利用扫描电子显微镜、X射线衍射仪及透射电子显微镜观察分析了含Cu和Mo(Ni-A)、不含Cu和Mo(Ni-B)两种镍基合金喷焊层样品的组织、相分布和成分分布,分别测定了基体部位、热影响区、结合区及涂层内的显微硬度.利用高频加热炉对两种喷焊层进行了热疲劳实验,对经热疲劳实验后喷焊层微观组织进行了观察,分析了喷焊层内的相分布和成分分布状态,探讨了热疲劳裂纹产生和扩展的过程及规律.结果表明:两种喷焊层内均有针状富Cr第二相弥散分布,具有较好的热疲劳性能.Ni-A样品喷焊层可以分成两个区域:在靠近基体的区域均匀地分布着块状富Cr第二相;在离表层200μm左右的区域内分布有针状富Cr第二相,体积比块状富Cr第二相小几十倍.Ni-B样品喷焊层内只有针状富Cr第二相,在整个喷焊层内均匀分布.Ni-A样品喷焊层由于过渡区域的存在,具有比Ni-B样品喷焊层更好的热疲劳性能.热疲劳实验前后样品的EDS分析结果表明两种喷焊层内的各相有较好的热稳定性.
The microstructure of two Ni-based alloy spray coatings including Cu and Mo (Ni-A) and without Cu and Mo (Ni-B) were observed by scanning electron microscopy, X-ray diffraction and transmission electron microscopy. And the distribution of the components, the microhardness of the substrate, the heat affected zone, the bonding area and the coating were measured respectively.The thermal fatigue tests of the two sprayed coatings were carried out by high frequency furnace, Layer microstructure was observed, the phase distribution and composition distribution in the spray coating were analyzed, and the process and rule of the generation and propagation of thermal fatigue crack were discussed.The results show that there are acicular Cr Two-phase dispersed distribution, with good thermal fatigue properties .Ni-A sample spray layer can be divided into two regions: in the region near the substrate uniformly distributed massive Cr-rich second phase; from the surface area of about 200μm The needle-like Cr-rich secondary phase is distributed in the inner part, and the volume is several tens times smaller than that of the massive Cr-rich secondary phase. Only the needle-shaped Cr-rich second phase is sprayed in the Ni-B sample spray layer, .Ni-A Sample Spray Welding Layer Due to the transition region, there is a better heat than the Ni-B sample spray coating LO performance before and after the thermal fatigue test samples EDS analysis results showed that each of the two phases within the spray layer has good thermal stability.