Effects of vacuum hot-pressed sintering parameters on the microstructures and mechanical properties and process optimization of TiB2p/Al7050 composites

Abstract

In this paper, TiB2p/Al7050 composites are studied, which lays a foundation for their development in aerospace materials and other fields. TiB2p/Al7050 composites were prepared by vacuum hot-pressed sintering, and the process parameters were optimized based on an orthogonal experiment. The effects of sintering temperature A, axial pressure B, and holding time C on density, hardness, and strength are studied by range analysis, analysis of variance, and multi-index matrix analysis. The calculation shows that the order of influence of each factor is C>A>B, then the important parameters of holding time and sintering temperature were explored. The results show that the relative density, microhardness, and tensile strength of TiB2p/Al7050 composites increase with the increase of holding time during sintering. Only the elongation increases first and then decreases at 600 °C, indicating that excessive holding time reduces the plasticity. The density, hardness, strength, and elongation increase first and then decrease with the increase in sintering temperature. Obvious porosity begins to appear after reaching 600 °C, resulting in performance degradation. The optimum process parameters were finally determined as 590 °C, 20 MPa, and 120 min, and the effects of other TiB2 mass fraction composites on microstructure and mechanical properties were studied to verify the superiority of the process. With the increase of TiB2 content, the relative density, hardness, and strength of the composites increase greatly, but the plasticity decreases gradually.