Shape memory alloy based NiTi reinforced functionally graded material for vibration damping

Abstract

Shape memory based high performance nickel-titanium alloy particles were embedded by friction stir processing in graded concentration on the surface of light weight commercially pure magnesium cast plates. The novel functionally graded material so developed was analyzed for microhardness evolution and vibration damping effect. The nickel-titanium alloy particles were filled in a 2.5 wide × 3 mm deep slot and embedded on the surface by friction stir processing. A shallower slot 2.5 wide × 1.5 mm deep was milled over the previously embedded surface in which nickel-titanium alloy powder was again filled and embedded on the surface by second pass friction stir processing. This sequence of pass created the graded variation in nickel-titanium alloy concentration. The so fabricated functionally graded material was cut out from the plate and it was hot-forged to 2/3 thickness and subsequently quenched. The microstructural examination confirmed homogeneous dispersion of nickel-titanium alloy particles and clear interface between high and low concentration regions. The microhardness confirmed a uniform graded variation in hardness. The vibration damping tests confirm considerable improvement in the damping capacity of the fabricated functionally graded material.