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采用固体YAG脉冲激光对预置一定配比的Ti/B混合粉末涂层进行激光熔覆,在TC4钛合金表面原位合成TiB_2陶瓷增强相。利用X射线衍射、金相显微观察以及显微硬度测试等手段,分别对熔覆样品的物相、组织形貌和显微硬度分布特征进行了研究。实验结果表明,激光功率为64W(其中电流140A,脉宽8～10ms,频率12～15Hz),扫描速度1.0～1.2mm/s,离焦量2mm时,可原位生成TiB_2陶瓷涂层。金相观察结果表明,熔覆层与基体结合处为波形界面,形成了良好的冶金结合。显微硬度沿截面纵向呈梯度分布,熔覆层的硬度较基底平均提高了3～4倍。
Solid YAG pulsed laser was used to laser cladding Ti / B mixed powder coating with preset proportion, TiB 2 ceramic reinforced phase was synthesized in situ on TC4 titanium alloy surface. The phase, microstructure and microhardness distribution of cladding samples were studied by means of X-ray diffraction, metallographic observation and microhardness test. The experimental results show that TiB_2 ceramic coating can be formed in situ with the laser power of 64W (current 140A, pulse width 8 ~ 10ms, frequency 12 ~ 15Hz), scanning speed 1.0 ~ 1.2mm / s and defocusing amount 2mm. Metallographic observation results show that the cladding layer and the substrate at the junction of the waveform interface, forming a good metallurgical bond. Microhardness gradient along the vertical distribution of the cross-section, the hardness of the cladding than the average increase of 3 to 4 times.