Multi-pass ultrasonic impact treatment (UIT) was applied to modify the microstructure and improve the mechanical and tribological characteristics at the near-surface region of commercially pure Ti (CP-Ti) specimens produced by the laser powder bed fusion (L-PBF) method. UIT considerably refined the L-PBF process-related acicular martensites (α′-M) and produced a well-homogenized and dense surface microstructure, where the porosity content of 1-, 3-, and 5-pass UITed samples was reduced by 43, 60, and 67%, respectively. The UITed samples showed an enhancement in their near-surface mechanical properties up to a depth of about 300 μm. The nanoindentation results for the 3-pass UITed sample revealed an increase of about 53, 45, and 220% in its nanohardness, H/E_r, and H³/E_r² indices, respectively. The stylus profilometry results showed that performing the UIT removed the L-PBF-related features/defects and offered a smooth surface. The roughness average (R_a) and the skewness (R_sk) of the 3-pass UITed sample were found to be lower than those of the L-PBFed sample by 95 and 223%, respectively. Applying the UIT also enhanced the material ratio, where the maximum load-bearing capacity (~ 100%) in as-L-PBFed (as-built) and 3-pass UITed samples was obtained at 60- and 10-µm depths, respectively. The tribological investigations showed that applying the UIT resulted in a significant reduction of wear rate and average coefficient of friction (COF) of CP-Ti. For instance, under the normal pressures of 0.05 and 0.2 MPa, the wear rate and COF of the 3-pass UITed sample were lower than those of the L-PBFed sample by 65 and 58%, and 20 and 17%, respectively.

采用多道超声波冲击处理 (UIT) 来改变激光粉末床熔合 (L-PBF) 生产的商业纯钛 (CP-Ti) 样品的近表面区域的微观结构并改善其机械和摩擦学特性方法。 UIT 显着细化了与 L-PBF 工艺相关的针状马氏体 (α′-M)，并产生了均匀且致密的表面微观结构，其中 1、3 和 5 道 UIT 样品的孔隙率含量降低了 43 、60%和67%。 UITed 样品的近表面机械性能在深度达到约 300 μm 时有所增强。 3 次 UITed 样品的纳米压痕结果显示，其纳米硬度、H / E _r和H ³ / E _r ²指数分别增加了约 53%、45% 和 220%。触针轮廓测量结果表明，执行 UIT 消除了与 L-PBF 相关的特征/缺陷，并提供了光滑的表面。发现 3 遍 UITed 样品的平均粗糙度 ( Ra ) 和偏度 ( Rsk ) 分别比 L _- PBFed 样品低 95% 和 223% _。应用 UIT 还提高了材料比率，其中分别在 60 µm 和 10 µm 深度处获得了 as-L-PBFed（竣工）和 3 遍 UITed 样品的最大承载能力（约 100%） 。摩擦学研究表明，应用 UIT 可以显着降低 CP-Ti 的磨损率和平均摩擦系数 (COF)。例如，在0.05和0.2 MPa的常压下，3道UITed样品的磨损率和COF分别比L-PBFed样品低65%和58%，以及20%和17%。