TC4表面丝粉同步激光熔覆制备复合材料层的微观组织和性能

Microstructure and Properties of Compound Layer Fabricated by Coincident Wire-powder Laser Cladding on Ti6Al4V Surface

针对Ti-6Al-4V耐磨性差的问题,采用激光熔覆技术在Ti-6Al-4V基材表面通过旁轴添加与基材同质的Ti-6Al-4V丝材,同轴送入WC颗粒作为强化相的方式制备表面WC颗粒增强钛基复合材料层。激光功率、扫描速度、送丝速度等工艺参数是影响复合材料层成形的主要工艺因素,通过实验确定了优化的工艺参数。采用SEM,EDS以及XRD对复合材料层的显微组织进行了研究。研究表明,复合材料层中主要包括WC、W_2C、Ti C、α-Ti、W相。复合材料层中WC颗粒呈现不同形态。Ti C、W_2C相形成并以不同形态分布于表面复合材料层中。WC颗粒与Ti之间的反应区由多层组成,分别为W_2C、W、Ti C。性能分析发现,复合材料层的硬度HV0.2达到了5.70 GPa,较基体提高了1倍。表面复合材料层的摩擦系数为0.3,而钛基体的摩擦系数为0.5。与基体相比,表面复合材料层摩擦系数显著降低。

The aim of this paper is to overcome the poor anti-wear properties such as high friction coefficient and low hardness of Ti6Al4 V alloy.Cladding of metal matrix composites（MMC） layer was conducted on Ti-6Al-4V substrate by coincident wire-powder laser deposition. During the experiment, the powder was fed from a coaxial nozzle and the wire was fed from a lateral nozzle into the deposition melt pool. Microstructure of the compound layer was analyzed by SEM, EDS and XRD. Results show that the compound layer mainly comprises WC, W_2 C, Ti C, α-Ti and W phase. Ti C, W_2 C phase is formed with different morphologies in different locations of the MMC layer. W_2 C, W and Ti C layer can be found at the interface of WC/Ti matrix. The HV_（0.2） hardness of the compound layer is 5.70 GPa, which is about 2 times of that of the substrate. The friction coefficient of MMC layer is 0.3, while that of Ti substrate is 0.5. Compared to the substrate, the friction coefficient of MMC layer declines significantly.