Microstructure and mechanical properties of multi-carbides/(Al, Si) composites derived from porous B4C preforms by reactive melt infiltration

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2012-08, Vol.551, p.200-208
• Main Authors: Wu, Hongyan, Zhang, Shengcai, Gao, Mingxia, Zhu, Dan, Pan, Yi, Liu, Yongfeng, Pan, Hongge, Oliveira, Filipe J., Vieira, Joaquim M.
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum; Aluminum base alloys; Bonding; Carbides; Composites; Condensed matter: structure, mechanical and thermal properties; Electron microscopy; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; Infiltration; Intermetallic compounds; Mechanical and acoustical properties of condensed matter; Mechanical characterization; Mechanical properties of solids; Melts; Physics; Preforms; Silicon; X-ray diffraction
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2012.05.008

► Multi-carbide-based composites were fabricated by reactive melt infiltration. ► The fabrication was performed by infiltrating Al–Si alloys into B4C preforms. ► The microstructure and the mechanical properties of the composites were studied. ► The fracture mode of the composites was discussed. ► The work provides a facile method in fabricating multi-carbide-based composites. Multi-carbides/(Al, Si) composites were prepared by a spontaneous reactive melt infiltration technique. B4C and B4C with extra carbon (B4C/C) preforms were infiltrated with Al–Si alloys with Si contents ranging from 36 to 80wt.%. The infiltration was conducted at temperatures 200°C above the liquidus of the Al–Si alloys. Influence of the composition of the Al–Si alloys on the structure and the correlation of the structure and the mechanical properties of the composites have been studied. The alloys show good infiltration ability to the B4C and B4C/C preforms. The Al–Si alloys reacted with B4C, forming new carbides. Composites composed of carbides of SiC, B4C, AlB12C2, Al3B48C2 and residual Si and Al are obtained. The typical upper values of Vickers hardness and flexure strength are 17±3GPa and 328±8MPa, respectively, which are provided by the infiltration couple of B4C/Al–55wt.% Si. The fracture mechanism of the composites has also been discussed.