Design of liquid-assisted self-healing metal-matrix composites

摘要

Advancements in materials science have enabled components to be fabricated lighter, stronger, and more functional than ever. However, damage mitigation in these materials still limits their usable lifetimes. Recently, materials with the ability to heal structural damage have shown promise as potential novel materials of the future. Within metallic-based systems, metal-matrix composites reinforced with shape memory alloys (SMA) have the potential to demonstrate dramatic capabilities in damage mitigation and repair.;Investigations of liquid-assisted self-healing in metal-matrix composites have centered on developing a high specific-strength matrix possessing a low-melting eutectic for use as the healing material. A systems design approach motivated by a thermodynamic-based methodology was used to determine appropriate matrix alloying elements for improved mechanical properties while maintaining healing capabilities. Initial research focused on improving a Sn-Bi matrix reinforced with commercial NiTi SMA wires. Healing was established at over 94% retained strength post-healing. Recent developments in aluminum-based alloys have shown potential healing across several systems.;This study will detail methodology used to design the prospective Al-based alloy systems and establish the efficacy of the design approach through prediction of strength, microstructure development, and SMA incorporation into the composite. In addition, mechanical behavior of several binary and ternary matrix alloy composites were investigated to determine how healing is affected by different alloying elements in Al. Advancement of healing behavior in an oxygen-containing environment through reactive element addition was also investigated. Finally, areas to advance future matrix and composite designs will be brought forth.