Effect of (Al-Ni) & (Cu-Ni) Concentrations Ratios on the Hardness and Porosity of Ternary (CuAl-Ni) Smart Alloys

Abstract

In this research, the newly achieved results determined the best ratio of (Cu-Ni) and (Al-Ni) in the smart (Cu-Al-Ni) alloys since these values achieved the best results in terms of, hardness and porosity. Their mechanical properties have great commercial and technological importance in many applications: industrial, aerospace & biomedicine and also in high damping composites, filters, prosthetic hands, sensors, actuators, self-lubricant applications, automobile industry, electronic industry...etc. (Cu-Al-Ni) smart alloys samples were produced using powder metallurgy technique with vacuum system. In this experimental setup, five weight percentages Cu-Ni & Al-Ni of ternary (Cu-Al-Ni) smart alloys were selected. Vickers micro-hardness and porosity properties of these alloys were studied using a digital Vickers micro-hardness tester, X-ray diffraction device (XRD), Optical microscopic device, Scanning Electron Microscope device (SEM) &Porosity testing in accordance to the ASTM B328-(1996) so as to show the effects of (Cu-Ni) & (Al-Ni) concentrations ratios on hardness & porosity of (Cu-Al-Ni) smart alloys. The analysis results proved that when there is an increase in Al and Ni concentration in alloy lead, it will automatically increase the hardness and porosity, but the increase in Al ratio shows more effect than the increase in Ni ratio. It is preferred to select the weight percentages of aluminum and nickel so that we get smart alloys that possess single martensitic phase (&#946'3 ) because when it increases the aluminum weight percentage above 14%. It leads to the production of single martensitic phase ( Y'3). This type of martensitic is brittle and causes heavy increase in its hardness, which makes it lose its ability to recover its original shape and confines it to limited use in applications at high temperatures. Finally, the best smart alloy is S5 (82.4%Cu,14%Al, 3.6%Ni), especially for applications such as (high damping composites & self-lubricant applications) because it gives the highest hardness (155.73 HV) and highest porosity (6.853% by volume) among the five samples studied.