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采用固体粉末渗硼法对TC4钛合金基体表面进行渗硼试验。通过扫描电镜(SEM)、能谱(EDS)与X射线衍射(XRD)研究TC4钛合金渗硼后的物相组成和组织形貌,讨论渗硼过程中元素的扩散行为。结果表明:在1000,1050和1100℃分别保温5,20h后,渗层由外表层的TiB2和内表层的TiB晶须组成,渗层厚度范围为0.8～15μm。XRD分析表明:TC4钛合金渗硼后形成TiB2与TiB双相硼钛化合物层,随着温度的升高,TiB2与TiB的峰位增多;EDS分析得出表层B原子被TC4钛合金吸附后与基体的Ti化合导致过渡区域内的Ti含量减少,同时Al和V元素开始向基体扩散并在近界面处富集。渗层的显微硬度呈梯度分布,TiB2到TiB晶须维氏硬度值的变化范围为22000～11000MPa,过渡区的硬度值要高于基体的硬度值。
Boronizing test on TC4 titanium alloy substrate by solid powder boronizing method. The phase composition and microstructure of TC4 titanium alloy after boronizing were studied by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The diffusion behavior of the elements in the boronizing process was discussed. The results show that the infiltration layer consists of TiB2 in the outer layer and TiB whiskers in the inner layer after heat preservation at 1000, 1050 and 1100 ℃ for 5 and 20 h, respectively, and the thickness of the diffusion layer ranges from 0.8 to 15 μm. XRD analysis shows that the TC4 titanium alloy forms a two-phase boron-titanium compound layer of TiB2 and TiB after boronizing, and as the temperature increases, the peak positions of TiB2 and TiB increase; EDS analysis shows that the surface B atoms are adsorbed by the TC4 titanium alloy, The Ti compounding of the matrix results in a reduction of the Ti content in the transitional region, while Al and V elements begin to diffuse towards the matrix and become enriched at the near interface. The microhardness of the diffusion layer is gradient distribution, the Vickers hardness value of TiB2 to TiB varies from 22000 to 11000MPa, and the hardness of the transition zone is higher than that of the matrix.