Chip formation characteristics of selective laser melted Ti–6Al–4V

Abstract

In this research work, chip formation characteristics of selective laser-melted (SLM) Ti–6Al–4V in both ‘as built’ and ‘heat treated’ conditions are studied and compared with conventional wrought Ti–6Al–4V. Machined chips and partially deformed chips were collected from turning trials and quick stop experiments to study the nature of chip formation characteristics. Chip formation studies reveal that, ‘segmented’ or ‘saw tooth’ chips were produced during machining of SLM Ti–6Al–4V materials. The tendency to form segmented chips was higher in SLM Ti–6Al–4V materials as compared to conventionally produced wrought Ti–6Al–4V. In addition, cracks were found to be a common feature in primary and secondary deformation zones of SLM Ti–6Al–4V chip samples, illustrating that periodic crack initiation is the root cause of ‘saw tooth’ formation during machining. Furthermore, the tendency to form build up edge during machining was less in SLM Ti–6Al–4V materials compared to wrought Ti–6Al–4V, influencing the machined surface finish.