Study On The Impact-abrasive Wear Behavior Of TC4 Titanium Alloy Treated By Laser Shock Peening

TC4 titanium alloy is favored by various industries due to its advantages such as low density,high strength ratio and excellent biocompatibility.It is widely used in aero engine turbine blades,medical implant artificial joints,steam turbine impellers and other key components.Due to the poor wear resistance of TC4 titanium alloy,the failure caused by friction and wear is the main reason for scrapping these parts.In this paper,aiming at the problem that the TC4 titanium alloy parts are easy to wear during service,the effect of initial impact kinetic energy on the impact abrasive wear behavior of TC4 titanium alloy were studied using the self-developed impact abrasive wear test equipment,and the evolution process and wear mechanism of impact abrasive wear were analyzed.The differences in the impact abrasive wear behavior of TC4 titanium alloys strengthened by laser shock peening with different parameters were compared,and the process parameters of laser shock peening that can significantly improve the wear resistance of TC4titanium alloys were determined using the analysis of variance.The following conclusions are obtained:1.Laser shock peening makes the surface grains of TC4 titanium alloy refined,and the grain uniformity becomes worse,but no phase change occurs.Micro-cracks and pores were generated on the surface of the strengthened area,and plastic deformation occurred.With the increase of the laser shock times or laser energy,the degree of grain refinement increases,and the plastic deformation becomes more serious,which results in an increase in the hardness and residual stress values of the surface layer.2.With the increase of the initial impact kinetic energy,the peak value of the impact contact force,the absorbed energy,and the wear volume of the laser-strengthened specimen increased by 307%,699%,and 24%,respectively.When the initial impact kinetic energy is relatively small,the center of the wear scar appears protrusions.As the initial impact kinetic energy increases,the wear scar center changes from protrusions to pits.3.The friction interface dynamic response and wear scar characteristics of TC4 titanium alloy strengthened by laser shock peening change significantly with the evolution of impact abrasive wear.When the impact cycles increases from 1×10~3 to 2×10~4,the wear area becomes larger,and the“buffer”effect of the sand particles increases.The peak value of impact contact force decreased significantly before 5×10~3 impact cycles,and then no longer changed significantly.The energy absorption rate increased from 87.57%to 96.74%.The center of the wear scar changed from protrusions to pits,and the wear volume increased by approximately1815%.4.The impact wear behavior of TC4 titanium alloy under the sand environment and no-sand environment shows a significant difference.The peak value of impact contact force and impact return velocity under the no-sand environment are approximately 137.7%and 41.2%greater than those under the sand environment.The wear volume under the sand environment is 68.6 times that under the no-sand environment.The impact wear mechanism under the no-sand environment is mainly spalling,delamination,cracking,and scratching,while under the sand environment,it is mainly ploughing,micro-cutting,and sand embedding on the surface of the TC4 alloys.5.The impact abrasive wear behavior of TC4 titanium alloy shows a difference with the change of the process parameters of laser shock peening.With the laser shock times or laser energy increases,the peak value of impact contact force and the impact return velocity during the wear process tend to increase,and the absorbed energy and wear volume tend to decrease.The analysis of variance results shows that the impact abrasive wear resistance of LSP-treated TC4 alloy is significantly improved when the laser energy reaches 7 J and the laser shock times reach three times,and the wear volume was about 43.9%lower than that of the untreated samples.