Effects of Al/Ni molar mass ratios and addition of CuO on the microstructure, mechanical properties, and energy release behavior of Al-Ni composites

Reactive Structural Materials (RSMs) are a new class of materials composed of two or more metallic materials with oxide-ceramic particles that are unable to ignite or explode under various types of loadings, such as thermal, mechanical, and electrical. This study aims to investigate the microstructure, thermal, physical and mechanical properties of the Al-Ni composites, as a type of RSMs, produced by mechanical alloying and subsequent hot pressing. In this research, the Al-Ni composites with various molar mass ratios of Al to Ni of 2:1, 1:1, and 1:3 were first produced. After determining the optimum molar mass ratio of Al to Ni concerning mechanical and thermal properties, Al-Ni composites were made by adding different amounts of CuO particles (2, 4, and 6 wt%), and their mechanical and thermal properties were determined. The thermal and mechanical results proved that the 1:1 molar mass ratio of Al to Ni in the Al-Ni composite exhibited optimal properties. The thermal properties of the Al-Ni-CuO composites showed that the general addition of CuO particles had a negative impact on the energy release of the Al-Ni composites. However, the combustion test showed that the presence of a low level of CuO particles (2 wt%) increased the reaction temperature from 1180 degrees C to 1368 degrees C. However, the higher content of CuO particles (4 and 6 wt%) reduced the reaction temperature of Al-Ni composites. Similar to the thermal properties, the mechanical tests proved the detrimental influence of CuO particles on the compressive strength and hardness values of Al-Ni composites. In-depth discussions on the affecting factors on the mechanical and thermal properties of the Al-Ni-CuO composites have been provided in this work.