Advanced Functional Materials for Health

**123**

**Chapter 9**

**Abstract**

Self-Healing in Titanium Alloys:

A Materials Science Perspective

Self-healing materials (SHM's) is an emerging class of smart materials, which are capable of autonomous or spontaneous repair of their damage under external stimuli, such as heat, light, and solvent, to the original or near original functionalities much like the biological organisms. The emergence of self-healing in metallic materials presents an exciting paradigm for an ideal combination of metallic and biological properties. The driving force behind this effort is to decrease the consequences of accidents, reduction of cost and extending the service life of metallic components. While previous reviews have focused on self-healing in polymers, composite, concrete and cementous materials, and ceramic, discussions about selfhealing in metallic materials remains scarce and the survey of literatures suggests Ti-based self-healing materials known to be biocompatible in human body is rare. The present chapter examines the art of self-healing in titanium-based alloys with the scope to provide an overview of recent advancements and to highlight current

**Keywords:** self-healing metals, self-healing coating, Ti-based alloys, shape memory

Historically, solving material reliability issues has been an old and long term quest of material scientist and engineers, due to their implications for material safety. Considering the fact that structural materials degrade irreversibly over time owing to proliferation of damage like microscopic cracks: the growth of which eventually results in failure. And most times, these internal defects or damage are deep inside materials and difficult to perceive and repair. Recently, there has been a huge interest in materials that can self-heal, as this property can potentially extend materials lifetime, minimize replacement costs, and improve product safety and reliability [1]. Thus, having materials with intrinsic self-repair capabilities—a sort of biomimetic healing functionality, may then allow failures to be averted and the

Although self-healing is an exclusive specialty of living organisms of biological origin and not easy to put in place in non-biological materials, continuous efforts are now being made to mimic natural materials and to integrate self-healing capability into polymers and polymer composites. Self-engineered healing properties, which are applied in closing and healing crack initiated in a material during its utilization, have been described in cementous [4] and polymer materials [5]. Selfhealing approaches mostly gained by surface modification [6–9] or by the creation

*Paul Sunday Nnamchi and Camillus Sunday Obayi*

problems and perspectives with respect to potential application.

useful lives of components and structures to be extended [2, 3].

effect (SME), autonomous repair, damage, design strategy

**1. Introduction and background**
