Microstructure and mechanical behavior of Cu–9Al–4Ni-3.5Fe-0.5Mn alloy fabricated by laser melting deposition

Abstract The Cu–9Al–4Ni-3.5Fe-0.5Mn Nickel-aluminum bronze (NAB) thin wall sample was prepared by laser melting deposition (LMD). The solidification characteristics, microstructure and mechanical properties were investigated. The LMD-NAB alloy consists of α, β′ and κ(κII, κIII, κIV) phase. The α phase shows directional growth trend along the deposition direction. Lamellar κIII phase distributed in α, and spherical shell κIII phase distributed on the surface of κIV phase were found. Spherical and parallelogram κIV phase was distributed in α phase. A core structure based on FeAl3 phase was located in the spherical and parallelogram κIV phase. The LMD-NAB alloy presents tensile properties with average ultimate tensile strength (UTS) of 645 ± 5.7 MPa and elongation of 21.2 ± 1.5% along the scanning direction, and tensile properties with average UTS of 637 ± 9.9 MPa and elongation of 26.0 ± 0% along the deposition direction. The fracture surfaces exhibit a mixture of brittle cleavage model and microvoid coalescence. This work shows great potential for fabricating NBA alloy by LMD technology.