Fe nanoparticles modified pure Ti alloy on microstructure evolution and fine crystallization mechanism fabricated by additive manufacturing

It has been confirmed that micro-alloying is the effective way to refine the grain size and elevate the properties of pure Ti alloy produced via additive manufacturing. The pure Ti, Ti–2Fe (wt.%) and Ti–4Fe (wt.%) alloys created via Laser Melting Deposition (LMD) are compared based on their grain size, orientation relationship, and mechanical properties. Ti–4Fe displays a significantly lower average grain size of 220 μm in comparison to pure Ti and Ti–2Fe alloys, with average size of 442.3 and 319.6 μm. The superior constitutional supercooling of the former is responsible for the decrease in grain size. The orientation of the α phase is found to be influenced by the solid solution of Fe, with greater Fe content resulting in a preference towards the (0 0 0 1) direction for growth. Furthermore, the inclusion of Fe led to a noteworthy increase in both the yields strength, peaking at 798 MPa, and tensile strength, reaching 880 MPa. This enhancement is attributed to both the fine grain strengthening (54.4%) and the solid solution strengthening of Fe atoms (45.6%).