Abstract
The influence of laser glazing on fatigue crack growth (FCG) in a titanium aluminide (Ti3Al) alloy Ti-24A1-11Nb has been studied. Glazing leads to retention of beta phase in the melt zone and is accompanied by a significant increase in hardness as compared to that of the base microstructure. Laser glazing strongly influences the FCG behavior. Crack growth rates (CGRs) at a given stress intensity are reduced by up to three orders of magnitude. Maximum retardation in the CGR is observed when the crack front is around 4.0 mm ahead of the laser track. The observed slowing of CGR can be understood on the basis of the superposition principle that accounts for the influence of residual stresses on FCG. The equilibrating compressive stresses resulting from the tensile thermal residual stresses reduce the local effective stress intensity and, thereby, lead to reduced CGRs. In the absence of residual stresses, when subjected to a thermal treatment (650 °C/100 h), no observable variation in CGR is noticed over the entire crack length that encompassed two laser tracks.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
