机械合金化法制备Ti-Al非晶复合涂层

Ti-Al Amorphous Composite Coating Prepared by Mechanical Alloying Method

摘要:

在室温条件下，采用机械合金化法在Ti6Al4V（TC4）表面制备Ti-Al非晶复合涂层，利用XRD、SEM、EDS及显微硬度测试等手段对涂层的表面物相、截面微观形貌、区域化学成分及显微硬度梯度进行分析。研究表明，涂层的形成经历了一个反复的“冷焊—变形—断裂”过程，涂层厚度的变化规律与球磨时间存在一定的关系，随着时间的延长，涂层厚度先增加后减小最后趋于稳定。当球磨转速为400 r/min、时间为12 h时，可形成厚度约为200 μm且组织致密的Ti-Al非晶复合涂层；涂层最大维氏硬度达5800 MPa，约为基体硬度的3倍；利用X射线衍射强度比较法测量涂层中非晶相的相对含量，得出球磨6 h时非晶相相对含量为49.53%，12 h后相对含量达96.35%

Abstract:

Ti-Al amorphous composite coatings were prepared at room temperature on the Ti6Al4V (TC4) substrates surface by means of mechanical alloying (MA). XRD, SEM, EDS and micro hardness test technique were employed to investigate surface phase, cross-sectional microstructures and micro-hardness of the coatings. The results show that the coatings are formed via a combination of cold welding, deformation and fracture processes. The coating thickness increased first, then decreased and finally verged to a constant value with increase of milling time; the as-synthesized coatings showed structures with high apparent density and free of porosity. Ti-Al amorphous composite coating, ~200 μm thick, was obtained when rotation speed was 400 r/min and milling time was 12 h. Meanwhile, it was also found that the maximum hardness HV0.1 value of the coating achieved 5800 MPa, which was about threefold higher than that of the substrate. The volume content of the amorphous phase in the coating amounted to 49.53% and 96.35% analyzed by the calculation of the X-ray diffraction intensity curve information when milling time was 6 h and 12 h respectively.