PREPARATION OF AL COMPOSITE BY FSP FOR HIGH PERFORMANCE APPLICATION

Abstract

NiTi alloys have the ability to regain their real shape after deformation by applying stress and temperature as induced transformations between austenitic and martensitic phases. This phenomenon is known as shape memory effect (SME) and these alloys are Shape memory alloys (SMAs). It is favorable to propose the SMAs into light alloys to produce special metal matrix composites (MMCs) having low density, high strength, and moderate Shape memory effect. Ni- Ti reinforced AA2024 bulk composites were prepared by friction stir processing with aim to have shape memory effect and good mechanical properties. Ni Ti particles were uniformly mixed in the Al metal matrix to form composites. At lower transverse speed and higher rotation speed, successful composites were prepared. Lower porosity and better mechanical properties were obtained with three-pass FSP. To observe the mechanical properties, hardness tests, XRD and differential scanning calorimeter (DSC) were conducted while microstructural properties of the - stirred zone were analyzed by Scanning Electron Microscope (SEM), Energy-Dispersive X-ray (EDX) spectroscopy etc. The slightly lower the tensile strength and lower elongation were reported of as-FSP composites than as-received AA2024. The results state that interfacial products such as Al3Ni, A13Ti, AlNi, Al3Ni2, Ni3Ti and NiTi2, being occurred in case of FSP which leading to lower interfacial bond strength. By results of DSC, were concluded that there is no any essence of shape memory effect without reinforcing Nitinol i.e; shape memory alloy rather than Ni and Ti particles only.