Friction stir processing of squeeze cast A356 with surface compacted graphene nanoplatelets (GNPs) for the synthesis of metal matrix composites

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

卷:769

Article

Kumar, Ajay P.¹  Madhu, H. C.^2,3  Pariyar, Abhishek²  Perugu, Chandra S.²  Kailas, Satish V.²  Garg, Uma⁴  Rohatgi, Pradeep¹ 

[1] Univ Wisconsin, Dept Mat Sci & Engn, Milwaukee, WI 53211 USA

[2] Indian Inst Sci, Mech Engn Dept, Bangalore 560012, Karnataka, India

[3] Siddaganga Inst Technol, Mech Engn Dept, Tumkuru 572103, India

[4] Univ Wisconsin, Dept Phys, Milwaukee, WI 53211 USA

关键词: Metal-matrix composites (MMCs);    Graphene;    Mechanical properties;    Microstructures;    Fractography;   

DOI  :  10.1016/j.msea.2019.138517

来源: Elsevier

【 摘 要 】

Friction stir processing (FSP) was applied to graphene nanoplatelets (GNPs) physically compacted on the surface of squeeze cast A356 alloy to incorporate GNPs within the matrix and to improve its mechanical properties. Squeeze casting resulted in finer size silicon and intermetallic compounds in cast microstructure, and subsequently FSP further refined the microstructure of squeeze cast A356 alloy, and GNP reinforced A356 alloy. The finer Si particles, intermetallics and graphene dispersed in the matrix increased the yield and ultimate tensile strength of FSP squeeze cast A356 alloy compared to the results reported in prior literature for FSP A356 alloy. Eutectic Si needles have been converted to fine spherical particles during FSP and were uniformly distributed within the nugget zone. The crystallite size of GNPs which were physically adhered to the surface of squeeze cast alloy prior to FSP decreased after FSP as a result of deformation. Thus, a combination of squeeze casting, and friction stir processing and incorporation of GNPs reinforcement in the A356 matrix is a promising route to further improve its mechanical properties.

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