Microstructure and mechanical properties of Cu-12 Al-6 Ni with Ti addition prepared by powder metallurgy

Abstract Owing to its excellent wear resistance and good mechanical properties, the sintered Cu-Al-Ni alloy is an ideal material for preparing sliding bearings and self-lubricating sleeves. Adding trace elements into the Cu-Al-Ni alloy is expected to further enhance these properties. Hence, in this work, the microstructure and properties of sintered Cu-12 Al-6 Ni alloys with varying contents of added Ti are studied. Results indicated that the NiAl, γ2, and α phases were distinctly refined when the Ti addition was 0.2 wt.%, and a small amount of the granular X phase ((Cu, Ni)2AlTi) appeared in the alloy. The X phase increased and coarsened with increasing Ti addition. When the Ti addition was 0.7 wt.%, pores appeared in the center of the large granular X phase. With increasing Ti addition, the sintered density of the alloys gradually decreased, while the hardness and tensile strength increased first and then decreased. When the Ti addition was 0.7 wt.%, the hardness reached the maximum (160 HB), while when the Ti addition was 0.2 wt.%, the tensile strength reached the maximum (412.2 MPa). Moreover, the friction coefficient and wear loss of the alloy were the lowest when the Ti addition was 0.2 wt.%. These findings can provide some theoretical guidance for fabricating high-performance Cu-Al-Ni powder alloys.