激光熔覆钛基梯度功能涂层组织和性能研究

Microstructure and property of laser cladding Ti-matrix functional gradient layer

为了改进钛合金的耐磨性能,开发在高温环境、大温度落差条件下使用的具有热应力缓和功能的新型涂层,应用Nd∶YAG激光在钛合金表面制备了钛基梯度功能耐磨涂层,观察了微观组织,分析了生成相,测量了梯度功能耐磨涂层、非梯度功能耐磨涂层和Ti600基体在大气环境室温下的摩擦磨损性能。结果表明,原位合成的TiC球状增强相弥散均匀分布在梯度功能耐磨涂层中,主要呈3种不同的形态,即粗大的或不完整的树枝晶、相对较为细小的等轴晶或近似等轴晶和细小短纤维状;梯度功能耐磨涂层和非梯度功能耐磨涂层表现出较优异的耐磨性能,摩擦系数和磨损率显著降低,平均是Ti600基体的0.3倍～0.5倍。

To improve the wear-resistance of Ti600, and alleviate thermal stress under hyperthermal and excessive temperature difference conditions, Ti-matrix functional gradient layer （FGL） on Ti600 substrate was prepared with pulsed Nd：YAG. The microstructure and phase composition of FGL were investigated. And the friction wear properties of FGL, N-FGL and Ti600 substrate were examined in atmosphere. It was found that a rapidly solidified microstructure, consisting of in situ synthesized TiC reinforced phase distributed on FGL substance evenly and dispersely in the form of globular grains, had three main different shapes, i. e. , bulky or imperfect arboreseent crystal, fine or approximately equiaxial crystal and chopped fibriform crystal. The wear resistance of FGL and N-FGL was improved obviously. Friction coefficient and wear rate decreased significantly, 0.3- 0. 5 times of Ti600 substrate.