In this study, Al-Ti-Zr and Cr-Ti-Zr metallic coatings with thichness of 250-280 μm were fabricated successfully on Zr alloy using pulsed laser cladding. By jointly employing multiple characterization techniques, microstructural characteristics of the coatings were probed with their formation reasons explored. The Al-Ti-Zr coating consists of a single BCC solid-solution phase (average size 8.6 ± 6.3 μm) with hardness of 405.5 ± 16.6 HV that is more than twice that of the substrate (198.7 ± 2.0 HV). Such marked hardening is mainly related to the contribution from the solid-solution strengthening produced by Al and Ti. The Cr-Ti-Zr coating consists of cellular BCC phase (average size 0.9 ± 0.4 μm) and C14-type Cr₂(Ti,Zr) Laves phase with nanoscale lamellar structures. Its average hardness is 584.8 ± 33.6 HV, about three times of that of the substrate, which can be ascribed to synergistic effects of solid-solution, grain refinement and second phase strengthening. The formation of the single BCC solid-solution phase in the Al-Ti-Zr coating is mainly due to the relatively small differences in atomic size and electronegativity between Al, Ti and Zr. For the Cr-Ti-Zr coating, however, due to large atomic size and electronegativity differences between Cr and Zr (as well as Cr and Ti), Cr₂(Ti,Zr) Laves phase was formed in addition to the BCC phase.

本研究采用脉冲激光熔覆技术在 Zr 合金上成功制备了厚度为 250-280 μm 的 Al-Ti-Zr 和 Cr-Ti-Zr 金属涂层。通过联合采用多种表征技术，探讨了涂层的微观结构特征及其形成原因。Al-Ti-Zr 涂层由单个 BCC 固溶体相（平均尺寸 8.6 ± 6.3 μm）组成，硬度为 405.5 ± 16.6 HV，是基材（198.7 ± 2.0 HV）的两倍多。这种显着的硬化主要与Al和Ti产生的固溶强化作用有关。Cr-Ti-Zr 涂层由蜂窝 BCC 相（平均尺寸 0.9 ± 0.4 μm）和 C14 型 Cr _2组成(Ti,Zr) 具有纳米级层状结构的 Laves 相。其平均硬度为584.8±33.6 HV，约为基体硬度的3倍，这可归因于固溶、细化和第二相强化的协同作用。Al-Ti-Zr涂层中单一BCC固溶体相的形成主要是由于Al、Ti和Zr之间的原子尺寸和电负性差异相对较小。然而，对于Cr-Ti-Zr涂层，由于Cr和Zr（以及Cr和Ti）之间较大的原子尺寸和电负性差异，除了BCC相之外还形成了Cr _{2 (Ti,Zr) Laves相。}