Improved surface integrity of Ti6Al4V fabricated by selective electron beam melting using ultrasonic surface rolling processing

作者：Liu, Zhongqiang; Gao, Chaofeng; Liu, Xiao; Liu, Ruiping; Xiao, Zhiyu^*

来源：JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, 2021, 297: 117264.

DOI：10.1016/j.jmatprotec.2021.117264

• Selective electron beam melting
• Ultrasonic surface rolling process
• Surface integrity
• Wettability
• Ti6Al4V

This paper investigates the effect of ultrasonic surface rolling processing (USRP) on the surface integrity, microstructure, hardness, and residual stress of selective electron beam melted (SEBMed) Ti6Al4V with as-built surface. Results show that the semi-melted powder and melting pool ridges are flattened due to the ultrasonic impact and static load, as well as surface defects, such as 'stairs' and holes, are eliminated. The surface integrity of the sample is significantly improved. The surface roughness Ra and Rz of the USRP treated sample with 800 N is reduced by -95 % and -90 %, the surface hardness is increased by -16.2 % compared with the as-built surface. A gradient microstructure and hardened layer exceeded 110 mu m is obtained. What's more, the surface wettability changes from hydrophobicity to hydrophily.