The microstructure of the Ti/Al weld seam (WS) was uniform, and a good metallurgy bond between TC4/5052 aluminum alloy substrates was obtained without obvious defects after the Tungsten inert gas (TIG) process. Then, a remelt layer (RL) with fine microstructure can be formed by means of a laser remelting (LR) technique of the Ti/Al TIG joints. The Ti–Al intermetallics were produced adhered to the weld joints’ surface, exhibiting the extreme high surface hardness. The micro-hardness distribution of this RL surface was in a range of 1150–1200 HV[Formula: see text], which was significantly higher than that of the TC4 titanium alloy substrate. The high micro-hardness of the weld joints’ surface can be mainly ascribed to the actions of the Ti–Al intermetallics, the fine grain and the solid solution strengthening.

中文翻译：

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Ti/Al TIG 焊接接头的激光表面加固

Ti/Al焊缝（WS）的显微组织均匀，经过钨极惰性气体（TIG）工艺后，TC4/5052铝合金基体之间获得了良好的冶金结合，无明显缺陷。然后，可以通过Ti/Al TIG接头的激光重熔（LR）技术形成具有精细微观结构的重熔层（RL）。Ti-Al 金属间化合物附着在焊缝表面，表现出极高的表面硬度。该RL表面的显微硬度分布在1150-1200 HV范围内[公式：见正文]，明显高于TC4钛合金基体。焊接接头表面的高显微硬度主要归因于Ti-Al金属间化合物、细晶粒和固溶强化的作用。