目的 研究在单晶表面喷砂预处理对MCrAlY-单晶高温合金界面的组织的影响。方法 对单晶基材进行不同载荷条件下的喷砂处理(包括无喷砂、轻喷砂及重喷砂)，然后采用超音速火焰喷涂(HVOF)工艺在单晶试样上制备MCrAlY涂层，观察高温氧化后涂层-单晶界面组织的演变。真空热处理后，首先对基材和涂层的微观组织结构进行扫描电镜观察表征，然后对涂层进行1 050 ℃的高温氧化试验，保温287 h后，继续采用背散射电子模式观察TCP相的析出行为，测量并绘制互扩散区和二次反应区析出厚度柱状图。结果 高温氧化热暴露过程中，涂层和基体之间发生了明显的元素互扩散现象，喷砂处理对互扩散区大小，尤其是二次反应区的深度，有着显著影响。在该高温氧化试验条件下，轻喷砂和重喷砂对互扩散区厚度的影响不大(重喷砂17.5 μm，轻喷砂20 μm)，但显著促进了SRZ的析出厚度(重喷砂52.5 μm，轻喷砂40 μm)。结论 喷砂会导致单晶内产生塑性变形(形成GPDZ)，且重喷砂会析出更深的二次反应区，对于包覆型MCrAlY涂层在单晶热端部件的表面应用，应当对单晶表面实施轻喷砂或无喷砂处理。

Favored by single crystal and γ/γ′ coherent structure, single-crystal superalloys possess extremely high strength and creep/fatigue resistance at high temperature, in which they can be utilized as structural material to fabricatekey hot-sectional components (e.g., blades) in aero or land-based turbine engines. Prior to service at high temperature, the components made by single crystal superalloy are compulsorily deposited with high temperature protective coatings (e.g., MCrAlY) to resist invasions by oxidation and hot corrosion, where a surface blasting is necessarily demanded before the coating procedure. To evaluate the influence of sand blasting on the microstructure change at the interface between the MCrAlY coating and single crystal superalloy, the specimens made of single crystal superalloy were sand blasted with different forces (no, slight or heavy), followed by deposition of the MCrAlY coating using the HVOF method. The purpose of present work is to observe the microstructure change at the coating/substrate interface and investigate the influence of sand-blasting craft on the microstructure evolution. Firstly, the coating samples experienced a typical vacuum treatment to reach homogenization and enhance bonding strength of the coating. After that, they were subject to an oxidation test in a muffle furnace at 1 050 ℃ for 287 h, where the precipitates of topologically close-packed phase (TCP) were observed by SEM under the back-scattered electron (BSE) mode, and the histograms of interdiffusion zone (IDZ) and secondary reaction zone (SRZ) thicknesses were profiled after oxidation. As indicated by the experimental results, a gamma prime depleted zone (GPDZ) was observed at the surface of the substrate for the coating sample right after slight-blasting, where nano scale Mo-rich particles were precipitated inside the GPDZ. After homogenization in vacuum, the substrate area below coating showed formation of IDZ and SRZ, where the IDZ location matched the region of original GPDZ. Below the IDZ, round-shaped TCP precipitates were finely distributed inside SRZ, which were much finer than the bright precipitates existed in IDZ. During oxidation, the total thicknesses of IDZ+SRZ showed approximately a linear rule to the oxidation time, which could be due to the presence of abundant defects in the GPDZ after sand-blasting. Experienced thermal exposure, the needle-like TCP phases were precipitated along 45° direction to the surface in which was the habit orientation of Ni-base single crystal superalloy. Compared withsamples with slightblasting or without blasting, the density and length of TCP precipitates formed in heavyblasting samples after 287 h oxidation were higher. Indeed, the sand blasting process applied a different influence on the thicknesses of IDZ and SRZ:the IDZ thicknesses were comparable (17.5 μm by heavy blasting to 20 μm by slight), but the SRZ thickness with heavy blasting was much higher (52.5 μm to 40 μm). Higher blasting force and larger alumina grits definitely cause severer deformation and destruction to the single crystal superalloy. As sandblasting would induce plastic deformation by forming GPDZ and formation of SRZ (thicker by heavy blasting), it is vitally important to control or reduce the blasting force before depositing a MCrAlY coating on the surface of single crystal superalloy components.