Effects of SiC Nanoparticle Content on the Microstructure and Tensile Mechanical Properties of Ultrafine Grained AA6063-SiCnp Nanocomposites Fabricated by Powder Metallurgy

• Published in: Journal of materials science & technology Vol. 33; no. 9; pp. 1023 - 1030
• Main Authors: Yao, X., Zhang, Z., Zheng, Y.F., Kong, C., Quadir, M.Z., Liang, J.M., Chen, Y.H., Munroe, P., Zhang, D.L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2017
• Subjects: grained; material; matrix; mechanical; Metal; Metal matrix nanocomposite; metallurgy; nanocomposite; Powder; Powder metallurgy; properties; Tensile; Tensile mechanical properties; Ultrafine; Ultrafine grained material; Metal matrix nanocomposite; Powder metallurgy; Ultrafine grained material; Tensile mechanical properties
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2016.09.022

Ultrafine grained AA6063-SiCnp nanocomposites with 1, 5 and 10 vol.% SiCnp have been fabricated by anovel powder metallurgy process. This process combines high energy ball milling of a mixture of 6063alloy granules made from machining chips and SiC nanoparticles and thermomechanical powder consoli-dation by spark plasma sintering and hot extrusion. The microstructure and tensile mechanical propertiesof the samples were investigated in detail. Increasing the SiC nanoparticle content from 1 to 10 vol.%,the yield strength and ultimate tensile strength increased from 296 and 343 MPa to 545 and 603 MParespectively, and the elongation to fracture decreased from 10.0%, to 2.3%. As expected, a higher SiCnanoparticle content generates a stronger inhibiting effect to grain growth during the thermomechanicalpowder consolidation process. Analysis of the contributions of various strengthening mechanisms showsthat a higher SiC nanoparticle content leads to a higher contribution from nanoparticle strengthening, butgrain boundary strengthening still makes the largest contribution to the strength of the nanocomposite.When the SiC nanoparticle content increased to 10 vol.%, the failure of the nanocomposite was initiatedat weakly-bonded interparticle boundaries （IPBs）, indicating that with a high flow stress during tensiledeformation, the failure of the material is more sensitive to the presence of weakly-bonded IPBs.