Researchers at Skoltech, together with colleagues from Russia and India, have adapted the selective laser melting method for the production of aluminum bronze parts. This material is in demand in components operating under high thermal loads — heat exchangers, cooled elements of power plants, and power electronics housings.
Aluminum bronze (Cu-9.5Al-1Fe) has higher thermal conductivity than steel and titanium, and is also better suited for 3D printing than pure copper. However, when working with copper alloys, two problems arise: high reflection of the laser beam and rapid heat dissipation. This leads to defects — non-fusion pores and the so-called "keyhole" porosity due to an unstable melt pool.
The scientists experimented with densities from 125 to 938 J/mm³, varying the laser power (90–150 W) and scanning speed (100–600 mm/s). At low energy, non-fusion pores appeared, and at high energy, "keyholes" appeared. The overall porosity level remained around 5%.
Despite this, the printed samples showed mechanical characteristics exceeding those of cast analogs: the tensile strength reached 748 MPa, and the elongation at break reached 16.2%, which is close to the parameters of nickel-aluminum bronze used in heavily loaded components.
Associate Professor Stanislav Evlashin of Skoltech explained that even on equipment with limited laser power, it was possible to achieve properties close to those of industrial bronzes. The key factor was understanding the transitions between different types of defects, which makes it possible to predict the properties of the material at the stage of selecting printing parameters.
The thermal conductivity of samples obtained with high energy density reaches 47 W/(m·K) at room temperature — this is close to the values of the cast material, but with significantly higher strength.