In-situ alloying of Ti-4.7Mo-4.5Fe alloy using laser powder bed fusion

¹ Department of Industrial Engineering, Stellenbosch University, South Africa
² Centre for Materials Engineering, Department of Mechanical Engineering, University of Cape Town, South Africa

^* Corresponding author: thuli@sun.ac.za

Abstract

This study used laser powder bed fusion to produce highly dense Ti-4.7Mo-4.5Fe through in-situ alloying. The relative density range of the printed samples was from 96. 3 to 99.5 %. Partially unmelted Mo and lack of fusion pores were observed on some samples produced using a laser power of 80 W with a high scanning speed. Better diffusion of Mo in the Ti matrix and pores were observed at a higher laser power of 164-200 W. The microhardness of the printed samples was higher than that of other β-Ti with Mo as β stabiliser and was comparable to the microhardness of the Ti-4.7Mo-4.5Fe alloy produced using conventional methods. The phase identification of the printed samples indicated that samples of Ti-4.7Mo-4.5Fe containing α+β phases were produced, with β being the dominant phase. Microstructural analyses showed that the lamellar α structure was embedded within the equiaxed columnar β grains.