Improvements of microstructure and mechanical properties of wire-arc directed energy deposition 2024 aluminum alloy after adding TiC nanoparticles
Xiaoyu Cai, Dongyuan Liu, Bolun Dong, Sanbao Lin
Abstract
To address issues such as grain coarsening, high porosity, and poor mechanical properties that commonly occur in high-strength 2024 aluminum alloy (AA2024) during directed energy deposition using an electric arc (DED-A), this work proposes a strategy of adding TiC nanoparticles to the AA2024 welding wire for DED-A and reveals the mechanism of TiC nanoparticles modification. AA2024 and TiCP/AA2024 composite were fabricated by DED-A. By adding TiC nanoparticles, the average grain diameter of the as-deposited TiCP/AA2024 composites considerably decreases from 65.4 μm to 16.4 μm. TiC nanoparticles refine the grains by promoting nucleation and inhibiting grain growth. Correspondingly, the mechanical properties of the as-deposited TiCP/AA2024 have been significantly improved: the horizontal tensile strength, yield strength, and elongation are 304 , 174 MPa, and 9.5%, respectively, which represent increases of 75%, 70%, and 164% compared to AA2024, and the tensile strength, yield strength, and elongation in the vertical direction are 287 MPa, 165 MPa, and 9.9%, respectively, with no significant anisotropy observed.