Effect of silicon addition on microstructure and properties of Cu–10Al–4Ni alloy prepared via powder metallurgy

Abstract Owing to its good mechanical properties and excellent wear resistance, Nickel Aluminum Bronze is used to manufacture critical components such as bearings, sleeves, and worm gears. Notably, trace elements can be added to further improve the properties of the alloy; therefore, in this study, the effects of different Si contents (0, 0.5, 1, 1.5, and 2 wt%) on the microstructure and properties of Cu–10Al–4Ni alloy were investigated. The results indicate that the alloy without Si comprised the α -Cu, Al 4 Cu 9 , and NiAl phases, whereas the addition of Si led to the refinement of the Al 4 Cu 9 and NiAl phases and an increase in their amounts. As the Si content increased, the sintering density of the alloys changed slightly, while the hardness initially decreased, then increased, and subsequently decreased again. The maximum hardness (136.3 HB) was achieved with an Si content of 1.5 wt%. Furthermore, the tensile strength initially increased and then decreased with increasing Si content, reaching its maximum value (397.4 MPa) at an Si content of 1.5 wt%. Hence, these findings may provide theoretical guidance for the development of high-performance Cu–Al–Ni powder alloys to better meet industrial requirements.