Effect of TiB2 on the Microstructure and Mechanical Properties of TiB2/Al-5Cu Matrix Composites

Particle reinforcement is a proven approach to optimize the microstructure and enhance the mechanical properties of Al matrix composites. In this work, a total of six compositions of TiB2/ZL205A(Al-5Cu) composites were fabricated by the mechanical stirring fusion casting process. The effect of TiB2 particles on microstructure and mechanical properties of composites was explored. The experimental results indicated that the grain structure of the composite material was significantly refined, with relative refinement of 23.3%, 32.1%, 42.4%, 49.5%, and 51.6%, respectively, after the addition of TiB2. With the increase of TiB2 content, TiB2 particles can be better attached near the second phase, while agglomeration occurs easily when the content is too high. The mechanical performance results show that the 2.0 wt.% TiB2/Al-5Cu composite material has the best mechanical properties, with tensile strength (TS), yield strength (YS), and elongation (EL) of 197.8 MPa, 113 MPa, and 7.35%, respectively. Compared to Al-5Cu matrix alloy, it has increased by 51.5%, 61.4% and 129.7%, respectively. Based on the experimental results, the strengthening mechanism of Al-5Cu composites by TiB2 particles was discussed in detail.