Influences of mg addition on the mechanical properties of Cu-Al-Ni shape memory alloys

Abstract EN

Shape Memory Alloys (SMAs) are a unique class of material that possessesunconventional properties such as the shape's memory effect, the high flexibilityassociated with damping capabilities, high wear resistance and fatigue.

Given itsuse in a variety of technological applications, its studies have attracted increasedinterest in the community of scientists and researchers during the past decades.

The shape memory alloy (Cu 83% -Al 13% -Ni 4% ) and the other alloy with addingthe alloying elements (Mg) with content of (0.25, 0.5, 0.75, 1.0, 1.25) % as avolumetric ratio which was taken from the copper percentage were prepared bypowder metallurgy, The powders were mixed using (V-type) powders mixer withmixing speed and time (20 rpm), (16 min) respectively then the samples werepressed by a two-way press (floating die) and pressing pressure (500 MPa) then thegreen samples where sintered by using vacuum furnace with using Argon gasmedium at a temperature (900°C) for one hour and left in the oven to cool down toroom temperature.

The results showed that both bulk density and apparent density compared to thebase alloy increase by increasing the volumetric fraction of Mg by the ratios(5.49)% compared to the bulk density of the base alloy and by the ratios (1.51)% compared to the apparent density of the base alloy.

accompanied by a decrease inthe real and apparent porosity and water orption, The results of the mechanicaltests showed an increase in the hardness and diametrical compressive strength withthe increase of volumetric fraction of (Mg) compared to the base alloyaccompanied by a decrease in the rate of wear, The (XRD) test observes thecomposing phases (α(Cu4Al), β(Cu3Al), γ(Cu9Al44)) in addition to determiningthe transformation temperature from the Martensite to the Austenite by examiningthe (DSC) it was found that the Austenite initiation and finish (As), (Af) increasedby adding the alloying elements (Mg).