This work characterizes microstructural evolutions of electron beam melted (EBM) Ti-6Al-4V alloy modified via laser shock peening (LSP). The depth stress distribution and tensile properties of EBM Ti-6Al-4V alloy were measured before and after LSP. The results indicate that microstructure consists of β phase with 7.2% ± 0.4% vol.% and balance α lamellar in EBM sample, and the α lamella was refined into nano-equiaxed grains and submicro-equiaxed grains after LSP. The dominant refinement mechanism is revealed during LSP. Stacking faults were found in the LSP-treated sample, and their corresponding planes were determined as (0001) basal plane, (10$\overline{1}$0) prismatic plane, and (10$\overline{1}$$\overline{1}$) pyramidal plane obtained by high resolution transmission electron microscopy. The subgrains and high-angle grains formed during dynamic recrystallization were identified by selected area electron diffraction pattern. The LSP treatment produces a significantly residual compressive stress approximately -380 MPa with the depth of compressive stress layer reaching 450 μm. Strength and elongation of the EBM sample were significantly increased after LSP. The strength and ductility enhancements are attributed to compressive stress, grain refinement and grain gradient distribution of α phase.

这项工作表征了通过激光冲击喷丸（LSP）改性的电子束熔化（EBM）Ti-6Al-4V合金的微观结构演变。在LSP之前和之后测量EBM Ti-6Al-4V合金的深度应力分布和拉伸性能。结果表明，微观结构由EBM样品中7.2％±0.4％vol。％的β相和平衡的α片层组成，经LSP处理后，α片层被细化为纳米晶和亚微晶。LSP期间揭示了主要的细化机制。在经过LSP处理的样品中发现了堆垛层错，并将它们对应的平面确定为（0001）基面，（10$\overline{\mathrm{1个}}$0）棱柱面，和（10$\overline{\mathrm{1个}}$$\overline{\mathrm{1个}}$高分辨率透射电子显微镜获得的锥面。动态重结晶过程中形成的亚晶粒和大角度晶粒可通过选定区域的电子衍射图来识别。LSP处理产生显着的残余压应力-380 MPa，压应力层深度达到450μm。LSP后，EBM样品的强度和伸长率显着提高。强度和延展性的提高归因于压应力，晶粒细化和α相的晶粒梯度分布。