Enhanced rolling contact fatigue behavior of selective electron beam melted Ti6Al4V using the ultrasonic surface rolling process

摘要

This paper investigates the influence of building directions and ultrasonic surface rolling processing (USRP) on rolling contact fatigue (RCF) performances of selective electron beam melted Ti6Al4V. Results show the RCF performance in the xoz direction is 54% higher than that of the xoy direction due to the poor crack propagation resistance of the prior-beta columnar grain boundary alpha layer. The USRP treated samples show similar to 30% longer RCF life than that of untreated samples. The increased RCF performance is attributed to large work hardening, surface nano-crystallization, surface residual compressive stress, and the changed lubrication condition from boundary lubrication to mixed lubrication, which suppresses crack initiation and propagation.

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