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在20钢基体上进行了激光熔覆0.8μm超细VC与Fe45合金粉末的实验,VC的百分含量分别为5%、10%、30%、50%。采用扫描电镜、维氏硬度计等设备检测了熔覆试样横截面的显微组织和性能。研究表明激光熔覆可以得到晶粒细化,析出相分布均匀,硬度高,与基体结合牢固的表面覆层;大部分VC在熔覆过程中熔化,在凝固过程中重新析出。随含量的不同,重新析出的VC分别呈现菊花状、树枝状、胞状形貌;Fe45熔覆层的平均硬度340 HV0.2,随着VC含量的增加,熔覆层平均硬度逐渐增加(530、615、833、987 HV0.2);随着VC含量的增加,单位时间内熔覆层的磨损失重逐渐减少,表明其耐磨损性能不断提高。
The experiments of laser cladding 0.8μm ultrafine VC and Fe45 alloy powders on 20 steel substrates were carried out. The percentages of VC were 5%, 10%, 30% and 50% respectively. The microstructure and properties of the cross-section of the cladded specimens were examined by scanning electron microscopy and Vickers hardness tester. The results show that laser cladding can obtain the surface coating with grain refinement, uniform distribution of precipitates, high hardness and strong bond with the matrix. Most of the VC melts during the cladding and re-precipitates during solidification. With the different content, re-precipitated VC showed chrysanthemum, dendritic and cellular morphology respectively. The average hardness of Fe45 cladding layer was 340 HV0.2. With the increase of VC content, the average hardness of the cladding layer increased gradually (530, 615,833,987 HV0.2). With the increase of VC content, the wear loss of cladding layer decreased gradually with the increase of VC content, indicating that the wear resistance of the cladding layer increased continuously.