Wear-triggered self-healing behavior on the surface of nanocrystalline nickel aluminum bronze/Ti3SiC2 composites

Highlights: • Wear-triggered crack healing is achieved on surfaces by decomposition and oxidation of Ti₃SiC₂. • The selective-formed SiO₂, TiO₂ and Al₂O₃ heal the cracks during fretting wear. • An improved tribological performance is associated with the self-healing process. Self-healing can protect materials from diverse damages, but is intrinsically difficult in metals. This paper demonstrates a potential method through a simultaneous decomposition and oxidation of Ti₃SiC₂ to achieve healing of stress cracking on the surface of nickel aluminum bronze (NAB)/Ti₃SiC₂ nanocrystalline composites during fretting wear. At the finest nanocrystalline materials, a crack recovery would be attained at 76.5%. The repetitive fretting wear leads to a modest amount of 'flowability' of Ti₃SiC₂ toward the crack, facilitating crack recovery. Along with the wear-triggered self-healing, the NAB/Ti₃SiC₂ shows an improved tribological performance with the stable decreased friction torque due to the formation of lubrication TiO₂ oxide.