Experimental study on the effect of different types of surface roughness on fatigue failure of titanium alloys
Roughness is a critical factor influencing the fatigue performance of titanium alloy TC17.This study ana-lyzed the influence of two types of surface roughness on the fatigue failure mechanism and estimated the corresponding fatigue strength.Fatigue testing of the TC17 titanium alloy was conducted using an ultrasonic fatigue testing system,with the surface roughness of the specimens quantitatively measured.Fracture characteristics of the fatigue test speci-mens were observed using a scanning electron microscope,and the effects of surface roughness parameters Ra and Rz on fatigue failure were analyzed.Fatigue strength predictions were made using the Murakami model and the micro-scopic scratch model,with surface roughness serving as the primary variable in both cases.The results indicate that both types of surface roughness significantly contribute to fatigue failure.Using Rz as the main variable,the distribu-tion of predicted fatigue strength results for TC17 closely aligns with the experimental data,and the predictions are considered safe.However,when Ra is used as the main variable,the predicted values are relatively lower.This study provides valuable guidance for the operation,maintenance,and performance evaluation of TC17 titanium alloy com-ponents in practical engineering applications.
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