SiC增强Ni35合金激光熔覆层的组织和性能

Microstructure and Properties of Laser Cladding SiC Reinforced Ni35 Alloy Layer

在45钢表面、不同激光功率(1000~1400 W)和扫描速度(6~10 mm·s^(-1))下激光熔覆质量分数20%SiC增强Ni35合金熔覆层,根据熔覆层宏观形貌确定最佳工艺参数,研究了最佳参数下熔覆层的组织和性能。结果表明:该激光熔覆层的最佳工艺参数为激光功率1000 W、扫描速度8 mm·s^(-1),该参数下熔覆层的组织为树枝晶和等轴晶,物相包括SiC、Ni4 B3、CrB、Ni2 Si和FeSi等硬质相;熔覆层的硬度约为45钢基体的3.5倍,在熔覆过程中激光淬火作用下热影响区的硬度高于基体的;熔覆层的磨损质量损失均明显小于基体的,且磨损质量损失随磨损时间延长的增幅较小,说明熔覆层耐磨性能较好;熔覆层磨损60 min时的磨损方式主要为黏着磨损,磨损120 min时为磨粒磨损。

20wt%SiC reinforced Ni35 alloy cladding layer was prepared on 45 steel surface by laser cladding at different laser power(1000-1400W)and scanning speeds(6-10 mm·s^(-1)).The optimal process parameters were determined according to the macromorpholgy of the cladding layer.The microstructure and properties of the cladding layer were studied under the optimal parameters.The results show that the optimal process parameters of the laser cladding layer were as follows:laser power of 1000 W and scanning speed of 8 mm·s^(-1).Under these parameters,the microstructure of the cladding layer consisted of dendrites and equiaxed crystals,and the phases included hard phases such as SiC,Ni4 B3,CrB,Ni2 Si and FeSi.The hardness of the cladding layer was about 3.5 times that of the 45 steel substrate,and the hardness of the heat affected zone was higher than that of the substrate because of laser quenching effect during cladding.The wear mass loss of the cladding layer was obviously less than that of the substrate,and the increase in wear mass loss with the prolonged wear time was small,indicating that the wear resistance of the cladding layer was relatively good.The main wear mode of the cladding layer was adhesive wear after wear for 60 min,and was abrasive wear after wear for 120 min.