Effect of the Mass Fraction of Ceramic Particles on the Porosity of Wear-Resistant Composites Fabricated by Combustion S
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UCTION
FABRICATING composites by incorporating ceramic reinforcements into a steel or iron matrix has attracted attention for their improved wear resistance, combined toughness and machinability properties related to the conventional steel or iron, and high hardness and good wear resistance related to the ceramic particles.[1–17] Among the various hard phases, TiC-TiB2 has promising potential in engineering applications under extreme conditions owing to their excellent combination of mechanical and electrical properties, as well as their good corrosion and oxidation resistance at high temperature.[18] In addition, compared to conventional WC- and TiC-based cermets, TiC-TiB2 composite-based cermets exhibit a higher hardness and chemical stability at high temperatures, and are regarded as a good alternative for wear-resistant GUILIN SUN, DINGDONG FAN, and SUFEN TAO are with the School of Metallurgical Engineering, Anhui University of Technology, Ma’anshan, Anhui 243002, P.R. China and also with the Key Laboratory of Metallurgical Emission Reduction & Resources Recycling, Anhui University of Technology, Ministry of Education, Ma’anshan, Anhui 243002, P.R. China. Contact e-mail: [email protected] Manuscript submitted November 21, 2017.
METALLURGICAL AND MATERIALS TRANSACTIONS A
applications. Therefore, TiC-TiB2 is widely used as reinforcements in steel- or iron-matrix composites.[19] Methods of fabricating TiC-TiB2 reinforced steel- or iron-matrix composites include powder metallurgy,[1–3] conventional casting,[4–7] carbothermic reduction,[8–10] and self-propagating high-temperature synthesis (SHS).[11–15] SHS is the preferred technique owing to its high productivity, low cost, and high-purity products. In a previous study, most TiC or TiB2 particles in reinforced steel- or iron-matrix composites reinforced the whole matrix, even if only a small area of the composite faced severe abrasion in practical applications, which is undoubtedly wasteful. Generally, Cr is used as an alloying element to improve the hardness of traditional wear-resistant steel, as well as ceramic particles. Therefore, in this work, reinforcements composed of a metal matrix (Fe and Cr) and ceramic particles (TiC and TiB2) were combined with the steel matrix by combustion synthesis at a pressure of 1.5 MPa. A higher mass fraction of TiC-TiB2 in steel-matrix composites may not only result in higher hardness and better wear resistance, but also higher porosity, which was not considered in the previous study. Therefore, the aim of this study was to elucidate the relationship between the mass fraction of the ceramic particles and the porosity.
Table I.
Experimental Conditions
The Experimental Conditions Pressure (MPa)
Raw Materials Quality (g)
Mass Fraction of CaF2 (Pct)
Mass Ratio of Fe/Cr
Mass Fraction of Ceramic Particles (Pct)
Al
2.00 2.00 2.00 2.00 2.00
4.00 4.00 4.00 4.00 4.00
5.00 10.00 15.00 20.00 25.00
26.16 24.77 23.40 22.02 20.65
1.50 1.50 1.50 1.50 1.50
II.
18.27 17.31 16.35 15.38 14.42
52.48 49.71 46.95 44.19 41.43
1.01 0.9
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