钛合金表面激光重熔微弧氧化层的组织结构及摩擦磨损性能

Microstructure and Wear Properties of Laser Remelted Micro-arc Oxide Coating on Titanium Alloy

为改善TC21钛合金表面微弧氧化(micro arc oxidation,MAO)涂层的微观结构致密性和耐磨性能,对MAO涂层进行了激光重熔改性,并对重熔后涂层的微观结构、成分、相组成以及硬度、摩擦磨损性能等进行了表征测试。结果显示,重熔MAO涂层由重熔外层、重熔内层和热影响层3层结构组成,其中外层和内层主要由Al_(2)TiO_(5)、rutile-TiO_(2)和α-Al_(2)O_(3)组成,热影响层由α-Ti和β-Ti转变组织组成,重熔MAO涂层的硬度显著增大。在摩擦磨损实验中,重熔MAO涂层摩擦系数低于MAO涂层和TC21钛合金基体,其磨损机制以粘着磨损为主,并伴有轻微的磨粒磨损。激光重熔MAO涂层显著提高了TC21钛合金摩擦磨损性能。

To improve the microstructure compactness and wear resistance of the micro arc oxidation (MAO) coating on the surface of TC21 titanium alloy,a laser remelting modification was performed on the surface of the MAO coating.The microstructure,composition,phase composition,hardness,and friction and wear properties of the remelted coating were characterized.The results show that the laser remelted coating consists of three layers:outer layer,inner layer,and heat-affected layer,of which the outer and inner layer are mainly composed of Al_(2)TiO_(5),rutile-TiO_(2) and α-Al_(2)O_(3),and the heat affected layer is mainly composed of α-Ti and the transformed β phases.The hardness of the remelted MAO coating increases significantly.The friction coefficient of the remelted coating is lower than that of MAO coating and TC21 substrate in the wear test.The wear mechanism of remelted coating is adhesive wear,accompanied by slight abrasive wear.Laser remelted MAO coating significantly improves the friction and wear properties of TC21 titanium alloy.