Selective Laser Melting of a bronze propeller with superior mechanical properties
Given its electrical conductivity and its excellent resistance to salt and water corrosion, bronze is still widely relevant in marine applications as well as in water propulsions and handling systems .
The mechanical properties at room temperature of Cu-10Sn bronze samples are presented that were built by selective laser melting using gas-atomized powders with average particle size 85+/-15 μm . They are compared to the benchmark characteristics of samples produced using casting. Using an SLM 250HL machine, samples built under argon atmosphere (using the following optimized processing parameters : scanning speed 210mm/s, laser power 271W, powder layer thickness 90μm and hatch distance 90μm) exhibit 99.7% density, measured using the Archimedes technique. The mechanical properties of Cu-10Sn depend directly of the microstructure formed during solidification  with no need for post-heat treatment.
Although the phases available are essentially similar – both microstructure exhibit dendrites of the alpha-Cu(Sn) phase along with an interdendritic (alpha+delta)-eutectoid - the refined SLM microstructure compared to the coarser cast microstructure is due to the faster cooling rate during solidification and significantly affects the mechanical properties:
These SLM properties are comparable to those of Cu-10Sn-2Zm-1.5Fe bronze cast alloys strengthened by iron nanoparticles .
 S. Scudino, C.Unterdörfer, K.G.Prashanth, H.Attar, N.Ellendt, V.Uhlenwinkel, J. Eckert, Additive manufacturing of Cu–10Snbronze - Materials Letters, May 2015, http://dx.doi.org/10.1016/j.matlet.2015.05.076
 Davis JR. Copper and copper alloys. Materials Park: ASM International; 2001.
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