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Ultrahigh Strength And Plasticity In Laser Rapid Solidified Al–Si Nanoscale Eutectics, Huai-Hsun Lien, Jyoti Mazumder, Jian Wang, Amit Misra

Department of Mechanical and Materials Engineering: Faculty Publications

As-cast Al–20wt.% Si alloys were processed via laser rapid solidification (LRS) techniques to create eutectic microstructures with nanoscale interconnected, nanotwinned Si fibers. LRS morphologies exhibit higher flow stress, exceeding 800 MPa and uniform plastic deformation above 20% compared to as-cast alloy that fractures at strains below 8% at flow strength of approximately 200 MPa. The strengthening mechanisms of LRS morphologies are interpreted in terms of the interfacial constraints: increase in yield strength as well as strain hardening rate due to nanoscale confined slip in fibrous Al–Si eutectic, and load transfer and eventual plasticity in the nanoscale Si fibers.