Zinc alloy ZA-8/shape memory alloy self-healing metal matrix composite

This work investigates incorporating NiTi Shape memory alloy (SMA) wires in a Zinc ZA-8 die casting alloy in an attempt to rebond damaged surfaces. This is accomplished by heating the damaged sample which returns the sample to its original shape and results in partial melting of the matrix. Samples were designed to determine which of the following methods of load transfer from reinforcement wire to matrix was more effective; namely (a) direct load transfer by interfacial bonding of the matrix and reinforcement or (b) indirect transfer by mechanical transfer to a bolt embedded in the matrix. In undamaged samples, it was found that the ultimate tensile stress increased with increasing volume fraction of reinforcement, but that strain hardening was considerably higher in the mechanical load transfer samples and only these types of damaged samples demonstrated any significant regained strength after the thermal healing treatment. Up to 30% of the original ultimate tensile strength and ductility was recovered by thermal healing treatment of the ZA-8/SMA metal matrix composite.