Suchergebnisse

The aim of this work is to investigate the influence of the addition of Cu on the microstructure and on the microhardness of a laser powder bed fusion (L-PBF)-fabricated AlSi10MgCu alloy. With this goal, AlSi10Mg+4 wt%Cu pre-alloyed powder was produced by gas atomization. Following a parameter optimization study, dense as-built specimens with a high relative density of 99.8% were fabricated. An outstanding microhardness value, exceeding 180 HV, was obtained after aging at 160 °C for 16 h. This value is similar to that of the high strength Al 7075 in the T6 condition. With the aid of analytical transmission electron microscopy, it was concluded that the origin of the observed excellent mechanical behavior could be attributed to the beneficial effect of Cu in reducing the Al-matrix cell size, and in increasing the density and decreasing the size of the Si-based nanoprecipitates at cell interiors. More specifically, it is proposed that the maximum hardness is associated to the development of Cu-rich GP-I zones, which act as precursors of Si nanoprecipitates. Overaging leads to a reduction in microhardness due to transformation of these GP-I zones into coarser θ'' precipitates and thus to a smaller volume fraction of larger Si-based nanoparticles. ; This work was funded by the European Union's Horizon 2020 Clean Sky 2 research and innovation program under grant agreement No 755610, project AlForAMA. The authors acknowledge the support from the topic manager, Leonardo Aircraft. CYW acknowledges the financial support from the Fundamental Research Funds for the Central Universities in China (grant number 3102019QD0415). MTPP would like to acknowledge funding from the Madrid region under the program S2018/NMT-4381-MAT4.0-CM.