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以Al80/Ti20(mass%)混合粉末为原料,采用冷喷涂法在低碳钢上沉积致密的Al/Ti基复合材料,对其在不同温度下(400、450、500、550和600℃)进行热处理,获得原位Al_3Ti金属间化合物颗粒增强Al基复合材料。采用扫描电镜、X射线衍射仪、显微硬度仪及磨损试验机研究了冷喷涂Al/Ti复合材料热处理前后的微观组织形貌、相结构、硬度及磨粒磨损性能的变化规律。结果表明:冷喷涂Al/Ti复合材料的相结构与喷涂粉末相同,涂层组织致密、颗粒间为机械结合;Al/Ti复合材料在450℃热处理后其局部区域开始通过扩散反应原位形成Al_3Ti金属间化合物,而在600℃热处理后初始Ti颗粒已全部转变为Al_3Ti金属间化合物颗粒,同时,涂层内部颗粒界面间结合显著改善,从而获得原位Al_3Ti/Al复合材料。随着热处理温度升高,原位Al_3Ti/Al复合材料硬度先下降后升高,而其磨粒磨损性能则在550℃热处理后显著增加。
The dense Al / Ti matrix composites were deposited on mild steel by cold spraying with Al80 / Ti20 (mass%) mixed powder as raw materials. Heat treatment to obtain in-situ Al 3 Ti intermetallic compound particle reinforced Al-based composite material. The microstructure, phase structure, hardness and wear behavior of cold-sprayed Al / Ti composites before and after heat treatment were investigated by scanning electron microscopy, X-ray diffraction, microhardness tester and wear tester. The results show that the phase structure of the as-sprayed Al / Ti composites is the same as that of the sprayed powders. The microstructure of the Al / Ti composites is dense and the particles are mechanically bonded. The Al / Ti composites begin to form Al_3Ti in situ through diffusion reaction after heat treatment at 450 ℃ Intermetallic compounds. However, the initial Ti particles have been transformed into Al_3Ti intermetallic compounds after heat treatment at 600 ℃. Meanwhile, the interparticle interface between the coatings has been improved significantly, and the in situ Al_3Ti / Al composites have been obtained. With the increase of heat treatment temperature, the hardness of in-situ Al 3 Ti / Al composites decreased firstly and then increased, while the abrasive wear properties of Al 3 Ti / Al composites increased significantly after heat treatment at 550 ℃.