| TC17 is a near-β type α+β dual-phase titanium alloy that is widely used in manufacturing components for aircraft engines such as fan compressor discs and centrifugal impellers,owing to its high specific strength,good fracture toughness,high hardenability,and wide forging temperature range.However,key components of aircraft engines are subjected to harsh working environments,which can cause failure in the form of ultra-high-cycle fatigue and frictional wear.Therefore,a surface strengthening method is crucial to improve its service performance.Wet shot peening(WSP)treatment technology,as a new type of shot peening technology,has the advantages of significant effect,low cost,and simple operation,and can effectively improve the surface structure of materials and enhance their mechanical properties.In this study,different WSP process parameters were used to treat TC17 titanium alloy surfaces,and the microstructure and properties,including surface integrity,microhardness,and residual stress,were studied,while its ultra-high-cycle fatigue and frictional wear properties were also tested.The main research results obtained are as follows:(1)The results of the microstructure and properties of TC17 titanium alloy treated by WSP show that the surface defects,surface roughness,and surface stress concentration of TC17 titanium alloy increase after WSP treatment.However,polishing after shot peening can reduce surface defects,decrease surface roughness,and alleviate surface stress concentration.In addition,a series of changes occurred in the surface structure after WSP treatment,including grain refinement,work hardening,and introduction of compressive residual stress.(2)The results of ultrasonic fatigue tests on TC17 titanium alloy showed that polishing treatment after WSP could significantly improve the ultra-high-cycle fatigue life of TC17 titanium alloy.By observing the fracture morphology,three fatigue crack initiation mechanisms were found in WSP-treated TC17 titanium alloy,including surface crack initiation mechanism,subsurface crack initiation mechanism,and MPT crack initiation mechanism.(3)By comparing the friction and wear tests of TC17 titanium alloy under different WSP parameters,the results showed that WSP treatment could effectively improve the anti-friction and wear properties of TC17 titanium alloy,with a maximum reduction of7.25 μm in wear depth and 22.6% in wear volume. |
