EBSD study of beam speed effects on Ti-6Al-4V alloy by powder bed electron beam additive manufacturing

Electron Beam Additive Manufacturing (EBAM) has a lot of advantages and has become an attractive manufacturing method to produce the Ti-6Al-4V alloy. In this study, four Ti-6Al-4V rectangular blocks were manufactured by the EBAM process with four different beam scanning speeds (Speed Function x-SF20, SF36, SF50, and SF65). Based on the experimental results, the beam scanning speed did show notable effects on the preferred orientation of the a phase in the Z-plane which presents a relatively strong < 2 <(1)over bar> (1) over bar 4 > and < 1 0 <(1)over bar> 0 > texture. However, with the increase of the beam speed, the intensity of the texture in the Z-plane decreases first and then increases. For the Y-plane, the preferred orientation direction of a changes from < 2 <(1)over bar> (1) over bar 1> (SF20), < 0 0 0 1 > (SF36, SF50) to < 1 0 <(1)over bar> 2 > (SF65) with their maximum intensity decreased from 13.58 to 8.85 times of the random intensity. Generally, the parts did not show outstanding anisotropic characteristics in hardness and elastic modulus. The SF50 sample presents the highest properties (Vickers hardness and elastic modulus) between the four parts, which results from its finest microstructure and the weakest texture. (C) 2018 Elsevier B.V. All rights reserved.