Experimental characterization of novel obsidian-reinforced Al-A354 cast alloy metal matrix composite

The development of composite materials provided a solution to the challenge of producing engineering materials with a combination of high strength and low weight. Metal matrix composites (MMCs) which are made with hard reinforcing particles embedded within a metal matrix phase are a popular class of composite materials in transportation, marine, and aerospace applications. This study aims to evaluate the properties of a novel Al-obsidian composite produced by a powder metallurgy process with varied wt.% of obsidian particles and sintering duration. Nine samples were prepared with 1 wt.%, 2 wt.%, and 4 wt.% of obsidian reinforcement by mixing, cold pressing, and sintering for 1, 1.5, and 2 hours. The experimental analysis revealed that adding 4 wt.% obsidian led to a remarkable maximum hardness of 84.87 HRB, achieved with a 2-hour sintering duration. Due to the uniform dispersion of particles and employed sintering duration, composites with a 4 wt.% of obsidian and 2-hour sintering time exhibited low porosity and high hardness. Advanced EDX analyses provided insights into the elemental composition of both aluminum and first-time-used obsidian materials. The study sheds light on the pivotal role of obsidian reinforcement in shaping the characteristics of Al-based metal matrix composites, offering valuable insights for further research and development in this field.