Fretting Wear Properties of TC4 Alloy under Different Surface Strengthening States

The work aimed to study the effect of friction coefficient, residual stress field and plastic strain field on the fretting wear properties of TC4 alloy after shot peening (SP) and ultrasonic surface rolling process (USRP) strengthening. The surface of TC4 alloy was strengthened by SP and USRP respectively. After strengthening, the surface roughness, residual stress and microhardness of the TC4 alloy were measured by experiments. Based on the improved Archard wear equation, a two-dimensional cylindrical/planar contact model of fretting wear was established in the ABAQUS finite element software. With the help of the subroutines SIGINI and HARDINI in ABAQUS, the residual stress field and the plastic strain field were respectively introduced into the UMESHMOTION subroutine, so as to explore the effect of friction coefficient, residual stress field and plastic strain field on the surface fretting wear performance after surface strengthening. It was found that the surface roughness of the original specimen increased after SP, but improved after USRP; The microhardness of the specimen after SP and USRP strengthening was 1.28 times and 1.23 times of the original specimen, respectively. The maximum residual stress of TC4 alloy after USRP is –550 MPa, and after SP is –380 MPa. After introducing the residue stress field, the wear depth of the specimen was significantly reduced. Compared with the original specimen, the wear depth of the USRP and SP specimens were reduced by 15% and 10% respectively. After the introduction of the plastic strain field, the wear depth of the TC4 alloy is reduced about 6%. It can be concluded that the greater the friction coefficient, the more severe the wear under the same conditions. The wear profile gradually shifts to the outside with the increase of the friction coefficient, and the wear depth in the contact center area also becomes deeper and deeper with the increase of the friction coefficient. The plastic deformation behavior becomes more obvious with the increase of the friction coefficient and eventually makes the area of plastic deformation become larger and larger. With the introducing of residual stress field and plastic strain field, the amount of wear is reduced, and the influence of the residual stress is more significant. Through the fretting fatigue test, it is found that the life of the specimen is significantly reduced after the fretting wear is added, and the USRP specimen has the best anti-wear performance. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.