Laser solid forming additive manufacturing TiB₂ reinforced 2024Al composite: Microstructure and mechanical properties

The 2024Al alloy and 3%TiB₂ reinforced 2024Al composite were fabricated using laser solid forming (LSF). Different from the LSF processed 2024Al with a large columnar grain and apparent preferential growth orientation, TiB₂ reinforced 2024Al composite presents texture-less structure, consisting of the dendrite and fine equiaxed structures. Some TiB₂ particles distribute within the Al matrix, others distribute along the grain boundaries and intertwine with the Al₂Cu phase. The incorporation of TiB₂ gives rise to significant grain refinement, which is one of the important reasons for the improvement of mechanical properties. Moreover, the TiB₂ reinforced 2024Al sample exhibits 284 MPa high tensile strength, 163 MPa yield strength, 108.5HV microhardness, and 18.7% excellent elongation.