Researchers Surprised by Counter-Intuitive Healing Process
Wouldn't it be nice if broken and cracked materials could repair themselves? Of course it would which is why researchers are searching for self-healing materials. Those at MIT have recently stumbled upon a way by which metals could self-heal, and it was such a surprising find, they had to recheck their work.
Normally one would expect that pulling on a piece of metal with a crack in it would cause the crack to grow. According to the MIT researchers, it may not be that simple. Their computer showed cracks actually sealing as tension was applied, though the cracks had to be of a special kind. Disclinations are a type of defect where the crack extends partially into a crystalline grain, but do not reach from one side to the other. This kind of defect was first discovered a century ago and can have such intense stress fields that the effects of an applied load can be reversed, forcing a crack to heal itself.
Currently this work is just theoretical, but if real metals and alloys can be made to self-heal like this, we could see substantially longer lasting materials in the future. Metal fatigue, possibly the most common cause of metal failure, can occur as nanoscale cracks build up, and potentially it is these cracks that can be healed with tension.