An experimental investigation on tensile properties of self-healing metal matrix composite reinforced by superelastic NiTi wires using taguchi method

In the current study tensile properties of a self-healing metal matrix composite with a matrix made of Sn-13%Bi alloy and Ni-Ti SMA wires as reinforcement have been studied experimentaly utilizing taguchi method in order to determine the effect of wires volume fraction, pre-strain and healing temperature on results. Matrix alloy was molten in furnace at 300℃ and was casted in a preheated metallic mold. SMA wires was installed inside the mold in different quantities (1, 2, 3 wires) and different pre-strains (0, 2, 4 percent). By considering 3 healing temperature and using L-9 taguchi array, specimens in 9 main state was fabricated and tensile tested until failure. After the first test and fracture, specimens was placed in a furnace at healing temperature for 24 hours and then another tensile test was conducted in order to calculate the amount of recovered mechanical properties and introduce the efficiency level of each parameter on healing effectiveness. Results show that the presence of 2 wires with 4 percent of pre-strain and consecutively 190℃ and 180℃ healing temperatures create the best circumstances to achive highest amont of self healing efficiency for ultimate tensile strength and toughness.