Microstructure and mechanical properties of Cu–12Al–xNi alloy prepared using powder metallurgy.

The study investigated the effect of nickel content on the microstructure and mechanical properties of Cu–12Al-xNi alloys prepared using powder metallurgy. The results indicated that the alloys investigated consisted of α-Cu and γ 2 (Al 4 Cu 9), containing less than 4 wt% Ni content. The α-Cu phase gradually increased, while the γ 2 (Al 4 Cu 9) phase gradually decreased as the sintering temperature increased. Both the strength and hardness of the alloy thus reduced. When the Ni content increased above 4 wt%, the NiAl phase precipitated at the grain boundaries, which resulted in an increase in the strength of the alloy. Additionally, the tensile strength reached a maximum of 390 MPa when the Ni content reached 6 wt%. The decrease in the tensile strength for higher Ni content was attributed to the formation of a NiAl phase network. And the addition of nickel did not significantly alter the sintering density of the alloy. The mechanisms of microstructure evolution and strengthening mechanisms were investigated and discussed. [ABSTRACT FROM AUTHOR]