Effect of helium as process gas on laser powder bed fusion of Ti-6Al-4V studied with operando diffraction and radiography

The utilisation of helium as process gas in laser powder bed fusion limits the generation Ti-6Al-4V hot and incandescent spatters enhances their cooling rate. In present study, operando X-ray diffraction using synchrotron X-rays permits to verify that rates experienced by deposited material are not significantly affected unlike spatters. Topography measurements top printed surface reveal lower roughness He-produced samples, attributed previously observed reduction with He thus a redepositions on surfaces. Operando radiography provides insights spatter formation mechanisms namely particle entrainment, agglomeration, melting spheroidization.HighlightsThe average samples produced is than Ar equivalentDeposited during LPBF use HeGrain size orientation similar when processing under Ar, He, mixture bothOperando identify