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采用无针搅拌头以600 r/min的速度对Q235钢基体表面热喷涂高速钢粉末涂层进行四道次搅拌摩擦加工。借助仪器进行微观结构观察,对硬度进行了测试。结果发现:从涂层到基体产生了有层次的渐变影响区,影响区深度达450μm;残余涂层与基体表面的缝隙界面已经消失,可见明显滑移线;影响区中部是等轴细晶区;影响区下部是晶粒变形区,流变线明显可见。元素面扫描分析结果表明:涂层和基体受到搅拌摩擦加工过程中的热力耦合作用,发生了元素互扩散。与未加工试样的显微硬度对比,影响区内组织的显微硬度显著提高。
A needleless mixing head was used to perform four-pass friction stir processing on the hot-sprayed high-speed steel powder coating on the Q235 steel substrate surface at a speed of 600 r / min. With the instrument for microstructure observation, the hardness was tested. The results show that there are gradational influence zones from the coating to the substrate, the depth of influence zone reaches 450μm. The interface between the residual coating and the matrix surface disappears and the slip line is visible. The middle part of the influence zone is the equiaxed zone ; The lower part of the affected zone is the grain deformation zone, the rheological line is obviously visible. Elemental surface scanning analysis results show that the coating and matrix are thermodynamically coupled during friction stir processing, and elemental mutual diffusion occurs. Compared with the microhardness of the unprocessed sample, the microhardness of the tissue in the affected area is significantly increased.