Fabrication and characterization of stir casting AA6061-31%B4C composite
(1. Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China;
2. School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;
3. Nuclear Materials Joint Laboratory, Tsinghua University, Shenzhen 518055, China)
2. School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;
3. Nuclear Materials Joint Laboratory, Tsinghua University, Shenzhen 518055, China)
Abstract: A sophisticated stir casting route to fabricate large scale AA6061-31%B4C composite was developed. Key process parameters were studied, microstructure and mechanical properties of the composite were investigated. The results indicated that vacuum stirring/casting, B4C/Mg feeding and ingots cooling were essential to the successful fabrication of AA6061-31%B4C composite. Chemical erosion examination verified the designed B4C content; X-ray fluorescence spectrometer (XFS) showed the chemical composition of Mg and Si in the matrix conformed to industry standards; scanning electronic microscope (SEM) and X-ray diffraction (XRD) revealed that B4C particles were evenly distributed in the composites with well dispersed Mg2Si precipitates. Tensile testing results showed that the AA6061-31%B4C composite had a tensile strength of 340 MPa, improved by 112.5% compared with AA1100-31%B4C composite, which is attributed to the enhanced strength of the matrix alloy.
Key words: Al-B4C alloy; metal matrix composite; stir casting; microstructure; mechanical properties