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

摘要:

为改善TC21钛合金表面微弧氧化(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三层结构组成，其中外层和内层主要由Al2TiO5，rutile- TiO2和α- Al2O3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，其磨损机制以黏着磨损为主，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。

Abstract:

To improve the microstructure compactness and wear resistance of the micro-arc oxidation (MAO) coating on the surface of TC21 alloy, a laser remelting modification was performed on the surface of the MAO coating. The microstructure, composition, phase composition, hardness, 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 is mainly composed of Al2TiO5, rutile-TiO2 and α-Al2O3, 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 MAO coating and TC21 substrate in the wear test. The wear mechanism of remelted coating is adhesive wear, accompanied by slight abrasive wear. Laser remelting MAO coating significantly improved the friction and wear properties of TC21 titanium alloy.