Fabrication, mechanical and thermal behaviors of antiperovskite manganese nitride Mn3.1Zn0.5Sn0.4N reinforced aluminum matrix composites

Lightweight aluminum matrix composites with excellent mechanical and thermal properties are urgently required in applications of aerospace, electronics and military industries owning dimensional stability and long-life span. Antiperovskite manganese nitrides can be regarded as ideal reinforcements due to their high mechanical properties , low negative thermal expansion and wide temperature ranges. In this paper, 30 vol % Mn 3.1 Zn 0.5 Sn 0.4 N/Al composites with Mn 3.1 Zn 0.5 Sn 0.4 N particle sizes of 130, 63 and 12 μm were fabricated by vacuum hot-pressing sintering under sintering temperatures of 450, 500 and 550 °C, respectively. Material phase analysis, microstructural characterization, and bulk density measurements of Mn 3.1 Zn 0.5 Sn 0.4 N/Al composites are conducted. Three-point bending and nano-indentation mechanical properties of Mn 3.1 Zn 0.5 Sn 0.4 N/Al composites are studied, while thermal expansion and conductivity of Mn 3.1 Zn 0.5 Sn 0.4 N/Al composites are also investigated. For the Mn 3.1 Zn 0.5 Sn 0.4 N/Al composite sintered at 450 °C with particle size of 130 μm, the Young's modulus of 87.35 GPa, flexural strength of 169.3 ± 7.60 MPa and flexural strain of 3.62 ± 0.09% are produced. Meanwhile, the lowest coefficient of thermal expansion of 3.14 ppm °C −1 and largest thermal conductivity of 126.2 ± 7.0 W m −1  K −1 are possessed as well. Semi-coherent and coherent interfaces of Al–Mn and Sn–Mn 3.1 Zn 0.5 Sn 0.4 N with a width of ~100 nm are determined, which clearly indicates the interfacial characteristics within the Mn 3.1 Zn 0.5 Sn 0.4 N/Al interfacial micro-zones. This work can provide a good understanding and guide for designing and preparing novel structural-functional composite materials with excellent mechanical and thermal properties.