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利用高速火焰喷涂在45钢表面制备了Ni60AA和DZ-WC-12Co硬质合金层,再采用5 k W连续CO2激光器进行激光熔凝。通过GX51金相显微镜观察显微组织,HXS-1000TAY维氏硬度计测量硬度分布,MM-W1B立式万能磨损试验机进行磨损试验。结果表明,激光熔凝显著地消除了硬质合金层中未熔硬质合金颗粒、孔洞及裂纹等缺陷,组织更加细小、均匀;激光熔凝后,硬质合金层的硬度提高,平均显微硬度高达647 HV0.3。在试验条件下,激光熔凝后的硬质合金层的摩擦因数从原来的0.1373降至0.0948,激光熔凝可明显改善涂层的耐磨性能。
The Ni60AA and DZ-WC-12Co cemented carbide layers were prepared on the surface of 45 steel by high speed flame spraying, and then laser fused by 5 kW continuous CO2 laser. The microstructure was observed by GX51 metallographic microscope, the hardness distribution was measured by HXS-1000TAY Vickers hardness tester, and the wear test was conducted by MM-W1B vertical universal wear tester. The results show that the laser melting significantly eliminates the defects in the cemented carbide layer, such as the grains, cavities and cracks in the cemented carbide layer. The microstructure is more fine and uniform. The hardness of the cemented carbide layer increases after the laser is fused, Hardness up to 647 HV0.3. Under the experimental conditions, the friction coefficient of the laser-fused cemented carbide layer is reduced from 0.1373 to 0.0948, and the laser melting can obviously improve the wear resistance of the coating.