Effect of Cr Addition on Microstructure and Mechanical Property of Cu-17Ni-3Al-1.2Fe Alloy

Effect of Cr addition on microstructure and mechanical property of Cu-17Ni-3Al-1.2Fe alloy were investigated by means of tensile testing, optical microscope (OM), scanning electronic microscope (SEM) and transmission electronic microscope (TEM). The results showed that the morphology and type of second phases which exist among dendrites change significantly with the addition of 0.85 wt % Cr. A lot of rod-like and multi-branched Cr-rich phases can be observed while the formation of Ni3Al is suppressed. However, Cr addition does not change the type of particle-like Ni3Al which evenly distributes in the matrix. With the addition of Cr in Cu-17Ni-3Al-1.2Fe alloy, the tensile strength, yield strength and Brinell hardness increase, especially the yield strength with the increase of 31%, however, the elongation decreases slightly.