机械冲击对高硬激光熔覆层力学性能与微观组织的影响

为减少高硬合金激光熔覆层缺陷，提出了一种将机械冲击作用于激光熔覆过程的工艺方法，在45钢轴表面制备了Ni基、Fe基和Co基三种高硬合金熔覆层，对比分析了机械冲击对熔覆层力学性能和微观组织的影响。研究结果表明：加载机械冲击可改善熔覆层表面熔覆质量，抑制裂纹的萌生；机械冲击对不同材料的熔覆层力学性能影响不同，Ni65WC试样的可承受最大载荷提高了26.2%，但断裂总伸长量却减小了约37%，Fe90试样的可承受最大载荷提高了21.3%，而且断裂总伸长量亦增大约21%，Sti6+3%WC试样的可承受最大载荷提高了9.04%，其断裂总伸长量无明显变化；机械冲击使微观组织明显细化，显微硬度提高。

Effects of Mechanical Shocks on Mechanics Properties and Microstructures of High Hardness Laser Cladding

In order to reduce the defects of high hardness alloy cladding layers, a new technique for the laser cladding processes was presented. The Ni based, Fe based and Co based three kinds of high hardness alloy cladding layers were prepared on the surfaces of 45 steel. The effects of mechanical shocks on the mechanics properties and microstructures of the cladding layers were compared and analyzed. Research results show that the surface cladding quality of cladding layers may be improved by loading the mechanical shocks, restrian cracks. Mechanical shocks have different impacts on mechanics properties of cladding layers of different materials. Ni65WC specimen may withstand the maximum load increased by 26.2%, but the total elongation is reduced by about 37%, the ratio of the maximum load to the Fe90 sample may be increased to 21.3%, and the total elongation is also approximately improved, the ratio of the maximum load to the Sti6+3%WC sample may be increased to 9.04%, no obvious changes in the total elongation. Mechanical impacts make the microstructure significantly refined, micro hardness improved.