Overview: Self-healing materials are inspired by natural biological materials that can heal themselves when injured. Incorporating the self repair function into inorganic systems has recieved a lot of interest from materials scientists in recent years. Most studies have focused on polymers, concretes and ceramics because they are easier to synthesize than metallic materials. Multiple significant challenges remain to increase the TRL of self-healing materials. Some of these challenges include: a) ensuring bonding between components, b) multicycle healing, c) autonomous activation of healing, d) predicting the influence of microstructural architecture, bonding, volume percent, distribution, and size of shape memory alloys or microballoons, and e) predictiction of the properties of self-healed materials. Metal matrix self-healing materials reinforced with shape memory alloys can provide engineering grade material properties with the ability to heal multiple times. Similarly treating the NiTi properly in fabrication can work to understanding and controling the mechanics of self healing to enable design. Recent studies have been performed on self-healing metal matrix composites (MMCs) consisting of tin-bismuth alloys to ensure a good bond between the components. Simultanious work was performed to create and understand the capability to close cracks and create crack closing loads that will resist external loading. This paper also reviews mechanics based analysis of crack closing capabilities with supporting experimental validation.
Authors: Nathan Salowitz, Volkan Kilicli, Xiaojun Yan, and Pradeep K. Rohatgi
Keywords: Self-Healing, Self-Healing Materials, Self-Healing Metals, Self-Healing Metal Matrix Composites, Mechanics, Ni-Ti