Microstructural characterization and analysis of nitinol-based self-healing metals matrix composite of A356 alloy produced by high-pressure die casting

Abstract

A self-healing non-ferrous metal-matrix composite is prepared by the high-pressure die-casting process. It includes casting set-up, sample preparation of metal matrix composite (MMC), microstructural characterization, and analysis of its ability to close the crack. Aluminum alloy (A356) is deployed as a matrix material in the MMC. Nitinol is a smart alloy produced by a combination of Nickel and Titanium in equal mass proportion. Apart from excellent mechanical properties it also exhibits super-elasticity and shape-memory effect. The wire of the Nitinol is integrated as reinforcement within the matrix of A356 alloy through a high-pressure die-casting process. The recovery percentage of the metal matrix composite and microstructural evaluation are reported. The deployment of shape memory wire provides the ability to recover the matrix material even from plastic strain by just heating the sample slightly above the activation temperature of the Nitinol wire. Microstructural evaluation indicates fair integration of the reinforcement within the matrix material. Gaining the ability for 30.27% angular restoration and 19.37% crack closer is a very positive sign for designing self-healing metallic materials.