High-temperature strength of boron carbide with Pt grain-boundary framework in situ synthesized during spark plasma sintering |
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| Affiliation: | 1. College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300222, People’s Republic of China;2. Tianjin Key Laboratory of High Speed Cutting and Precision Machining, Tianjin University of Technology and Education, Tianjin 300222, People’s Republic of China;3. Centre for Infrastructure Engineering, School of Computing, Engineering and Mathematics, Western Sydney University, Penrith NSW 2751, Australia;1. DEN-Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France;2. Univ. Limoges, CNRS, IRCER, UMR 7315, F-87000, Limoges, France;1. Department of Mechanical Engineering, MANIT, Bhopal, India;2. Department of Mechanical Engineering, GRIET, Hyderabad, India;3. Department of Chemistry, RKDF University, Bhopal, India;4. Department of mechanical engineering MANIT, Bhopal,MP, India;1. Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA;2. II-VI M Cubed Technologies, Inc., Newark, DE 19711, USA;1. Chongqing Key Laboratory of Nano–Micro Composite Materials and Devices, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China;2. College of Aerospace Engineering, Chongqing University, Chongqing 400030, China |
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| Abstract: | Grain boundaries, twins, and defects are considered to influence the thermomechanical behavior of any covalent ceramic, as a result, monolithic B4C samples show different curve shapes of bending strength vs temperature and the present theoretical models fail to fit them over the entire temperature range. To overcome these issues, we fabricated a novel high-density boron carbide and evaluated its high-temperature bending strength. The as-obtained ceramic is composed of boron carbide grains and a fine grain-boundary metal Pt framework. The material shows a decreased strength, which is due to a non-linear increase in the volume expansion coefficient of the B4C. Recovery in strength above 1000 °C is due to the presence of twins, their growth and rearrangements. We consider twins rearrangements are the pieces of evidence for a novel ‘micro’ mechanism of high-temperature stress accommodation for the boron carbide bulks. |
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| Keywords: | Boron carbide Pt framework Modified grain boundaries Spark plasma sintering Bending strength Asymmetric twins |
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