FUNCTIONALLY GRADIENT LAYERS OF TI-AL BASED ALLOYS PRODUCED BY LASER ALLOYING AND CLADDING

Laser surface alloying and cladding have been used with the aim of producing functionally gradient materials based on the Ti-Al system. A continuous powder feed into a laser generated melt pool produced several fully overlapping layers of increasing Al content. Alloying involved feeding powdered Al onto a near-alpha Ti alloy substrate. For cladding, powder mixtures of Al and Ti-6Al-4V (wt-%) alloy were used with a Ti substrate of commercial purity. Cladding involving low dilutions provides a better approach to producing several discrete layers of increasing Al content than does alloying which is associated with higher dilutions. Structural and compositional data are reported for samples containing up to four layers having Al contents of up to approximately 34.5 wt-% (48 at.-%).