为探讨铝元素在激光微熔池中真正能实现的作用, 借助 Nd:YAG激光在 TC4表面分别进行了Ti＋w(Al)＝(1％～8％)激光熔覆实验。观测了微观组织、显微硬度和摩擦磨损性能随铝含量变化规律, 分析了生成相, 并定量分析生成有序化琢2相(Ti3Al为基)时的铝含量。结果表明, 微观组织由粗大的或不完整的树枝晶、相对较为细小的等轴或近似等轴晶和网篮状柱状晶组成。铝含量(质量分数 ,％)为 6时, 熔覆层中即有琢2相(Ti3Al为基)生成。随铝含量增加, 显微硬度呈上升趋势, 最高为 900 HV, 是铝含量(质量分数 ,％)小于 6时试样的 1.3～1.5倍。耐磨性能逐步提高, 摩擦系数和磨损率均呈降低趋势, 而且以 Ti3Al基琢2脆性相的生成为转折点, 生成后为生成前的 0.5～0.7倍左右。

To explore proper effects of aluminium in laser micro-molten pool, experiments of laser cladding Ti＋(1～8)%wt Al on Ti-6Al-4V by Nd:YAG had been carried out. The microstructures, microhardness and phases of the cladding layers with different weightpercentage of Al were investigated. The content of Al was quantitatively determinated when ordering琢2 ceramic phases (Ti3Al matrix)were formed. And the friction and wear properties were examined in atmosphere. It was found that the microstructure included bulkyor imperfect arborescent crystal, fine or approximately equiaxial crystal and columnar crystals. The琢2 ceramic phase was formedwhen the content of Al was 6%wt. With the increasing of weight percentage of Al, microhardness increased obviously. The maximumwas 900 HV, 1.3～1.5 times of the layers with below 6% wt Al. Inversely, the wear resistance of the laser cladding layers wereimproved gradually. Friction coefficient and wear rate decreased, 0.5～0.7 times of the layers with below 6%wt Al.