OPTIMAL PROCESS PARAMETERS FOR IN SITU ALLOYED Ti15Mo STRUCTURES BY LASER POWDER BED FUSION

Abstract

Powder Bed Fusion (PBF) is a manufacturing method with the advantage that it can produce objects of complex geometry. Additionally, it opens great opportunities to synthesize new materials from elemental powder using an in situ alloying approach. Potential of the in situ PBF alloying approach is nevertheless not well understood due to lack of experimental knowledge and information on the influence of process parameters on the microstructure, homogeneity and properties of the final materials. This investigation is focused on Ti15Mo alloy that was chosen as a promising β-type alloy for biomedical applications due to low Young’s modulus, close to the mechanical properties of bones. Geometrical characteristics of single tracks were investigated at a wide range of laser powers and scanning speeds. Threshold of enthalpy ratio to transition from conduction to keyhole mode was found. To study the distributions of molybdenum in Ti matrix, X-ray nanoCT scans and SEM EDS were performed. Effects of hatch distance and scanning strategy on the layer surface morphology were investigated. Microstructure and mechanical properties of as-built specimens were analyzed. Illustrated effects of each process parameter on the synthesized material is paramount to successful manufacturing of advanced implants with mechanical properties close to bones.