选区激光熔化成形Ti6Al4V合金摩擦磨损性能的各向异性

基于选区激光熔化技术制备了Ti6Al4V钛合金,研究了不同成形表面(XOY、XOZ)和不同载荷(20、40、60、80 N)对Ti6Al4V合金摩擦磨损性能的影响。通过摩擦系数(COF)结合磨损体积损失对不同成形面的摩擦磨损性能进行评估,采用光学显微镜(OM)、三维轮廓测量仪等设备对磨损轨道的形态和磨损机理进行表征。结果表明:相比XOZ面,XOY面在法向载荷为20N时其磨损体积减少了0.27×10-5 mm3,平均摩擦系数更小;而当载荷大于20N时,XOY面的磨损体积和平均摩擦系数均大于XOZ面。磨损轨道犁槽的深度和宽度随着载荷的增加而增加,犁槽呈现出明显的剥落行为,轨道处分布着块状的"粘合剂",发生着粘着磨损和氧化磨损。从摩擦系数、磨损体积、微观形态的角度定量反映出SLM成形Ti6Al4V合金的XOZ面比XOY面具备更优异的摩擦磨损性能,只有在低载荷下XOY面才表现出更加耐磨的特性。

Friction and wear performance of different forming surfaces of Ti6Al4V alloy formed by Selective Laser Melting

Ti6Al4V titanium alloy was prepared by selective laser melting technology. The effects of different forming surfaces (XOY, XOZ) and different loads (20N, 40N, 60N, 80N) on the friction and wear properties of Ti6Al4V alloy were studied. The friction and wear properties of different forming surfaces were evaluated by friction coefficient (COF) combined with wear volume loss, and the wear track morphology and wear mechanism were characterized by optical microscope (OM) and three-dimensional profile measuring instrument. The results show that compared to the XOZ surface, the wear volume of the XOY surface is reduced by 0.27×10-5mm3 when the normal load is 20N, and the average friction coefficient is smaller. However, when the load is greater than 20N, the wear volume and average friction coefficient of XOY surface are larger than those of XOZ surface. The depth and width of the plough groove of the worn track increase with the increase of the load. The plough groove exhibits obvious peeling behavior, and there is a blocky "adhesive" distributed on the track, causing adhesive wear and oxidative wear. From the aspects of friction coefficient, wear volume and micro-morphology, it is quantitatively reflected that XOZ surface of Ti6Al4V alloy formed by SLM has better friction and wear performance than XOY surface, and XOY surface shows more wear resistance only under low load.