Effect of grain size reduction of AA2124 aluminum alloy powder compacted by spark plasma sintering

• Published in: Journal of alloys and compounds 2014-10, Vol.609, p.215-221
• Main Authors: Eldesouky, A., Johnsson, M., Svengren, H., Attallah, M.M., Salem, H.G.
• Format: Article
• Language: English
• Subjects: AA2124; Aluminum base alloys; Aluminum oxide; Applied sciences; Ball milling; Compressive strength; Consolidation; Cross-disciplinary physics: materials science; rheology; Density; Exact sciences and technology; Grain size; Materials science; Mechanical milling; Mechanical properties; Metal powders; Metals. Metallurgy; Nano-powder; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Powder metallurgy. Composite materials; Production techniques; Spark plasma sintering
• ISSN: 0925-8388; 1873-4669; 1873-4669
• DOI: 10.1016/j.jallcom.2014.04.136

•Nano- and microcrystalline AA2124 alloy was produced through mechanical milling and sintering.•Two sintering techniques have been used Spark Plasma Sintering (SPS) and Hot Pressing (HP).•The mechanical properties were higher for specimens produced via SPS compared to their HP counterpart.•Nanocrystalline specimens had higher hardness and compressive strength but lower ductility.•Specimens processed via SPS grew a whisker-like aluminum oxide structure on fractured surfaces. Nanocrystalline (Average grain size ∼200nm) bulk AA2124 alloy was produced through high energy ball milling of microcrystalline powder followed by spark plasma sintering (SPS) at 480°C with a holding time of 10min. The effect of initial particle and grain size on the microstructural evolution as well as on the relative density and mechanical properties of the specimens consolidated through SPS and hot pressing (HP) at the same temperature for 60min was investigated for ball milled nano-powders (NP), as well as as-received micro-powders (MP). Results showed that the NP specimens consolidated with SPS had the highest microhardness values compared to the other specimens despite not achieving full densification. On the other hand, a general increase in density, hardness, and compressive strength was observed for all SPS consolidates compared to HP. The presence of aluminum oxide and its influence on the consolidation process as well as the resulting mechanical properties of the bulk specimens is also discussed.