Home-Skoltech Finds a Viable Path for 3D Printing Aluminum Bronze
Researchers fromSkoltech, part of theVEB.RF group, and collaborating institutions in Russia and India have turned their attention to one of additive manufacturing’s most closely watched material frontiers: copper alloys. Their work shows that with carefully tuned process parameters, laser powder bed fusion can produce aluminum bronze components that match, and in certain cases exceed, the performance of parts made through conventional manufacturing methods.
The findings, published inMaterials Characterization, open a credible route to printing heat exchangers, power electronics enclosures, and cooling components with complex geometries, parts where both thermal performance and structural integrity are non-negotiable.
Why Copper Alloys Have Been Difficult to Print
Aluminum bronze (Cu-9.5Al-1Fe) sits in an interesting middle ground: it conducts heat better than steel or titanium and is more amenable to additive processing than pure copper, yet it has remained difficult to print reliably. The root of the problem lies in the material’s physics. Its high reflectivity deflects laser energy, while its capacity to dissipate heat rapidly makes consistent melting hard to achieve.
By systematically varying laser power between 90 and 150 W and scanning speed between 100 and 600 mm/s, the team mapped energy density across a broad range, from 125 to 938 J/mm³. Two distinct defect regimes emerged: at lower energy inputs, insufficient melting produced lack-of-fusion porosity, while excessive energy density induced keyhole instability, where melt pool collapse traps gas beneath the surface. Regardless of the parameter set applied, total porosity consistently settled near 5%.
Strength Without Sacrificing Conductivity
Despite that residual porosity, the printed samples delivered mechanical results that challenged conventional expectations. Tensile strength reached 748 MPa and elongation hit 16.2%, figures that place the material in the same performance bracket as nickel-aluminum bronze, a grade typically reserved for demanding industrial applications and not commonly associated with additive processes.
“We were able to show that even using equipment with limited laser power, it is possible to achieve mechanical properties close to those of industrial nickel-aluminum bronzes. The key factor turned out to be not just increasing the energy input, but understanding the mechanisms governing the transition between different types of defects. This allows us to predict material properties at the stage of selecting printing parameters,” shared Associate Professor Stanislav Evlashin from the Materials Center, a co-author of the study.
Phase composition proved equally revealing. The extreme cooling rates inherent to laser melting, reaching up to 10⁷ K/s, drove crystallization far from equilibrium, giving rise to phases absent in conventionally processed aluminum bronze: Al₂Cu interlayers and Cu₃Fe nanoparticles. Crucially, higher energy density was found to suppress the phase fraction most responsible for hardness and strength, though this trade-off carried implications for electrical and thermal conductivity.
Source: 3D Printing Industry
