Microstructure and mechanical properties of a heat-treatable Al-3.5Cu-1.5Mg-1Si alloy produced by selective laser melting

Pei Wang*, Christoph Gammer, Florian Brenne, Konda Gokuldoss Prashanth, Rafael Gregorio Mendes, Mark Hermann Rümmeli, Thomas Gemming, Jürgen Eckert, Sergio Scudino

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    Abstract

    A heat-treatable Al-3.5Cu-1.5Mg-1Si alloy is successfully fabricated by selective laser melting and is investigated concerning microstructures and mechanical properties. The as-prepared samples show a fine-granular microstructure in the individual melt pool of the tracks and a coarse-granular microstructure in the areas between the tracks. After T6 heat treatment, the grain size of the specimens increases slightly and the Q phase formed in the as-prepared specimens transforms to Al2Cu(Mg), Mg2Si, and AlxMny. All Al-Cu-Mg-Si specimens before and after heat treatment fracture around the defects that were generated during processing and show intergranular fracture along columnar grains upon tensile quasi-static loading. The as-fabricated samples exhibit a yield strength (YS) of 223 ± 4 MPa and an ultimate tensile strength (UTS) of 366 ± 7 MPa with an elongation of 5.3 ± 0.3%. After T6 heat treatment, the YS and UTS increase dramatically to 368 ± 6 MPa and 455 ± 10 MPa due to the formation of nano-sized Al2Cu(Mg) precipitates, while the ductility remains fairly similar.
    Original languageEnglish
    Pages (from-to)562-570
    Number of pages9
    JournalMaterials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
    Volume711
    DOIs
    Publication statusPublished - 10 Jan 2018

    Keywords

    • Al-Cu-Mg-Si alloy
    • Heat treatment
    • Mechanical properties
    • Microstructure
    • Selective laser melting

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