Effects of electrolyte on hardening in laser hole sealing of commercially pure grade 1 titanium

Following laser hole sealing the hardness of CP1 Ti welds was found to be directly related to the microstructure. It was observed that welds made with electrolyte present had a microstructure which consisted mostly of the acicular alpha phase compared to welds made without electrolyte which had a mixed structure of serrated alpha, platelet alpha and acicular alpha phases. The hardest regions of welds made in the presence of electrolyte consisted of a fine colonized acicular alpha phase. Results from energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis further suggested that an increase in the composition of interstitial elements was the primary mechanism responsible for increased hardness when welding with electrolyte present.