Direct Energy Deposition - Laser Additive Manufacturing of Titanium-Molybdenum alloy: Parametric studies, microstructure and mechanical properties

Abstract

In this novel research, the Direct Energy Deposition - Laser Additive Manufacturing (DED-LAM) process is used for deposition of β-type Titanium Molybdenum (Ti-15Mo) biomedical alloy. A major challenge in the successful deposition of an alloy powder on the substrate by the DED-LAM process is the formation of a strong metallurgical bond with minimum track dilution. Targeting a crack-free and dense multi-layer deposition, a detailed investigation of the effect of three key process parameters on the track geometry characteristics is conducted. The response surface methodology (RSM) experimental design technique and ANOVA based quadratic regression modeling are employed to relate the process parameters with track geometric characteristics. The statistical analysis results show that minimum track dilution is achieved at maximum laser power and minimum scan speed and powder feed rate. Further, microstructural characterization is carried out to analyse the porosity, elemental composition and phase constituents. Microhardness of 385 ± 8 HV and elastic modulus of 73 ± 1.5 GPa are achieved for the Ti-15Mo deposits at the optimum parameter settings. This study establishes a methodology towards successful deployment of the DED-LAM process for potential fabrication of Ti-15Mo alloy biomedical implants.