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为提高钛合金表面强度,采用预置Tribaloy700(T700)合金粉末的方法在TA2钛合金表面进行了激光熔覆制备Ni基T700涂层的研究。研究结果表明,通过激光熔覆能够获得良好的T700合金涂层;涂层中Ti的适量存在能够促进laves相的析出与长大,Ti稀释较小时涂层组织主要为胞状和胞-枝蔓状的奥氏体γNi相,而Ti稀释较大时涂层组织为基体(TiNi+γNi相)+Laves相;涂层与基材之间有一厚约80~100μm的过渡区。显微硬度测试结果表明,在固溶强化及细晶强化等作用下T700熔覆涂层的显微硬度较常规方法有明显提高,适量的Ti稀释能够进一步提高涂层的硬度。根据Ti稀释程度的不同,涂层的平均硬度值在700~1000HV之间,约比TA2钛合金基材高4~5倍。
In order to improve the surface strength of titanium alloy, the laser cladding of TA7 titanium alloy on the surface of TA2 titanium alloy was used to prepare the Ni-based T700 coating by using the preset Tribaloy700 (T700) alloy powder. The results show that good T700 alloy coating can be obtained by laser cladding. Precipitation and growth of laves phase can be promoted by proper amount of Ti in the coating. When Ti is thinned, the microstructure of the coating is mainly cellular and dendrite Austenite γNi phase, while the coating of TiNi + γNi phase + Laves phase is formed when the Ti is thinned. The transition zone between the coating and the substrate is about 80 ~ 100μm thick. The results of microhardness test show that the microhardness of T700coated coating is obviously improved compared with the conventional method under the action of solid solution strengthening and fine grain strengthening. The appropriate amount of Ti can further improve the hardness of the coating. According to the different degree of Ti dilution, the average hardness of the coating is between 700 ~ 1000HV, which is about 4 ~ 5 times higher than the TA2 titanium alloy substrate.