The effects of ultrasonic nanocrystal surface modification on the fatigue performance of 3D-printed Ti64

• Published in: International journal of fatigue Vol. 103; pp. 136 - 146
• Main Authors: Zhang, Hao, Chiang, Richard, Qin, Haifeng, Ren, Zhencheng, Hou, Xiaoning, Lin, Dong, Doll, Gary L., Vasudevan, Vijay K., Dong, Yalin, Ye, Chang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2017; Elsevier BV
• Subjects: Additive manufacturing; Aerospace industry; Bending fatigue; Biocompatibility; Compressive properties; Fatigue; Materials fatigue; Mechanical properties; Metal fatigue; Modifications; Nanocrystals; Porosity; Residual stress; Residual stresses; Surface finish; Surgical implants; Three dimensional printing; Titanium base alloys; Ultrasonic nanocrystal surface modification; Ultrasonic testing; Surface finish; Fatigue; Additive manufacturing; Ultrasonic nanocrystal surface modification; Residual stresses; Porosity
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2017.05.019

•Ultrasonic nanocrystal surface modification (UNSM) were used to process 3D-printed metals.•Better surface finish, lower subsurface porosity were observed after UNSM treatment.•Tensile residual stresses were changed to compressive after UNSM treatment.•Significant improvement in fatigue performance was observed. 3D-printed metals have great potential for application in the biomedical and the aerospace industries. Unfortunately, they suffer from poor surface finish, high porosity, and high tensile residual stresses, leading to inferior mechanical properties as compared with traditional cast or wrought metals. In this study, we introduce an innovative method, ultrasonic nanocrystal surface modification (UNSM), for the processing of a 3D-printed Ti-6Al-4V alloy. The surface finish, microstructure, residual stresses and mechanical properties of the samples before and after UNSM treatment were characterized and compared. It was found that the UNSM treatment resulted in much better surface finish, lower subsurface porosity, and a high magnitude of compressive residual stresses, leading to significant improvement in rotation bending fatigue performance.