Investigation of Surface Nanocrystallization on a Commercially Pure Titanium TIG Weld Joint

摘要

Commercially pure Titanium TIG weld joint was treated by using a shot peening equipment commonly used in industry. The nanostructured surface layer was characterized by XRD, TEM, SEM and Microhardness tester. The results showed that surface nanocrystallization of commercial pure titanium TIG weld joint were realized by high energy shot peening treatment. The finest grain size in the top surface layer is about 40nm, and the depth of nanostructured layer was over 100 micrometers in HAZ and matrix. The hardness of the surface layer is enhanced significantly after shot peening compared with that of the initial sample, which resulted in a remarkable surface hardening effect. Surface welded defects such as air pores are eliminated successfully so that relative uniform surface layer is obtained.