Abstract
? 2022 Elsevier B.V.Laser powder bed fusion (LPBF) is a powerful technique for in-situ alloy development for advanced mechanical properties. This study used LPBF to dissolve TiC in a Ti-6Al-4V matrix and investigated how post-processing heat treatment and carbon content lead to improved strength and ductility. Pre-alloyed Ti-6Al-4V powder was mechanically mixed with up to 1 wt% TiC before undergoing LPBF. A comprehensive set of heat treatments was examined using 0.75 wt% TiC as a model composition. 1 h at 500 °C was deemed suitable for high strength applications, and 3 h at 700 °C was deemed suitable for a good mix of strength and ductility. TiC concentration was then varied from 0 to 1 wt% across both heat treatments. In the high-strength heat treatment, strength was improved to up to 1490 MPa with a ductility of 3.0% using 1 wt% TiC. Remarkably, with a heat treatment of 3 h at 700 °C, both strength and ductility increased to 1170 MPa with 11.5% ductility using 0.5 wt% TiC. These improvements are shown to be caused by solid solution strengthening and the pinning of prismatic dislocation slip.
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