Modification of As-cast Al-Mg/B4C composite by addition of Zr

JOURNAL OF ALLOYS AND COMPOUNDS

卷:685

Article

Rezayat, M.^1,2  Bahremand, M. R.¹  Parsa, M. H.¹  Mirzadeh, H.¹  Cabrera, J. M.² 

[1] Univ Tehran, Sch Met & Mat Engn, Coll Engn, POB 11155-4563, Tehran, Iran

[2] Univ Politecn Cataluna, ETSEIB, Dept Ciencia Mat & Ingn Met, Ave Diagonal 647, E-08028 Barcelona, Spain

关键词: Metal-matrix composites;    Liquid-solid reactions;    Mechanical properties;    Scanning electron microscopy;    X-ray diffraction;   

DOI  :  10.1016/j.jallcom.2016.05.226

来源: Elsevier

【 摘 要 】

Zirconium was used in Al-Mg/B4C composite to improve compocasting efficiency by increasing particle incorporation. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) results revealed that by addition of zirconium a reaction layer containing Zr, Al, B and C is formed on the interface of B4C-matrix. X-ray diffraction (XRD) analysis of extracted particles unveiled that the ZrB2 phase is the main constituent of this layer. Formation of ZrB2 is an exothermic reaction which can rise temperature locally around particles and agglomerates. Rising temperature around agglomerates in conjunction with turbulent flow of melt facilitates agglomerates wetting and dissolving into molten aluminum. As the result, final product contains more uniformly distributed B4C particles. Besides enhancing compocasting efficiency, addition of Zr and formation of reaction layer by improving particle matrix bonding quality, led to increase in ultimate tensile strength and elongation of the composite around 8% and 30%, respectively. SEM observations of the fracture surfaces confirmed that a proper bonding presents at the interface of particles and matrix in presence of Zr. (C) 2016 Elsevier B.V. All rights reserved.

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