Effect of Ag Nanoparticles Addition on the Physical and Mechanical Properties of (NiTi) Shape Memory Alloys Prepared by Powder Metallurgy

Abstract

Nickel-Titanium shape memory alloys (Nitinol) are considered as smart alloys due to their properties, such as Shape Memory Effect (SME) and Superelasticity (SE). These alloys are used in a wide range of applications that include (actuators, automobiles, robotic systems, medical uses, civil structures and aerospace).The article presents a study of the effect of adding Ag nanoparticles on the physical and mechanical properties of NiTi-based alloy, with different volumetric percentages of Ag (Ag= 0, 8, 9, 10, 11, 12) %. The samples were prepared by powder metallurgy means. The process involved three main steps, mixing, compacting and sintering. Physical and mechanical properties included microstructure, hardness, density, porosity, wear rate, diametrical compressive strength; XRF, XRD and SEM analysis were studied. The results showed an increasing in density and decreasing in porosity with increasing Ag content and the maximum hardness value was (280 Hv) at (11 %) of Ag content. XRD examination shows that the sintered samples are consisting of two phase's martensite (B19') and austenite (B2) at room temperatures in addition to (Ni, Ti, Ag, Ni2Ti, TiO, Ni4Ti3 and AgTi) structures were identified.