Effect of the heat treatment on the microstructure and hardness evolution of a AlSi10MgCu alloy designed for laser powder bed fusion

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:819

Article

Martin, A.¹  San Sebastian, M.²  Gil, E.²  Wang, C. Y.³  Milenkovic, S.¹  Perez-Prado, M. T.¹  Cepeda-Jimenez, C. M.^4,5 

[1] IMDEA Mat Inst, C Eric Kandel 2, Madrid 28906, Spain

[2] LORTEK S Coop Technol Ctr, Arranomendia 4A, Ordizia 20240, Spain

[3] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Xian 710072, Peoples R China

[4] Ctr Nacl Invest Metalurg CENIM CSIC, Dept Phys Met, Avda Gregorio Amo 8, Madrid 28040, Spain

[5] CENIM CSIC, Dept Phys Met, Avda Gregorio Amo 8, Madrid 28040, Spain

关键词: Aluminium;    Laser powder bed fusion;    Additive manufacturing;    Microstructure;    Precipitation hardening;   

DOI  :  10.1016/j.msea.2021.141487

来源: Elsevier

【 摘 要 】

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 degrees 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 theta precipitates and thus to a smaller volume fraction of larger Si-based nanoparticles.

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