The Effect of the addition of Ta, Zr and in on the corrosion behaviour of CuAlMn alloys prepared via powder metallurgy

Abstract

CuAlMn-X (X= Ta, Zr and In) shape memory alloy was fabricated using the powder metallurgy (PM) technique. After sintering at 950 °C, the products were processed using two heat treatments (solution heat treatment at 900 °C and aging at 500 °C). The influence of Tantalum (Ta), Zirconium (Zr) and Indium (In) with three wt.% on the mechanicals properties (hardness), corrosion behaviour and microstructure of CuAlMn shape memory alloys was investigated in this paper. The effect of the addition of Ta, Zr and In alloys was investigated using X-rays diffraction (XRD), open circuit potential, electrochemical tests (Tafel extrapolation method) and Vickers micro-hardness. For the corrosion tests, a 3.5 % NaCl (chloride solution) was used as corrosion solution. The results showed that there is an increase in hardness with addition of the alloy element (Ta, Zr and In) and decrease in the size of martensite plate form, as shown in the microstructures. Furthermore, it was found that the corrosion resistance of Cu-Al-Mn after the addition improved, as shown by the increase in the corrosion potential and decrease in the corrosion current densities. The improvement percentage for CuAlMnTa, CuAlMnIn and CuAlMnZr in the corrosion rate was 97 %, 91 % and 77 %, respectively.