Papers by Keyword: Carbide Particle

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Authors: A.A. Petelina, V.A. Youkhanov, A.D. Shur
Abstract: During the exploitation of the atomic power stations the tubing metal is exposed to the influence of temperatures in the range of 290-320С. It can lead to thermal ageing and to the decrease of the embrittlement resistance. The critical embrittlement temperature is the main value which is needed to calculate the embrittlement resistance of materials. The metal properties degradation is taking into account by introduction of the shift of critical embrittlement temperature. The presented data ensure the prognosis of tube steels properties and shift of the critical embrittlement temperature for 60 years resource.
Authors: S. Chakthin, Nuchthana Poolthong, Ruangdaj Tongsri
Abstract: Sintered Fe-5 wt. % carbide (SiC or TiC) composites have been prepared via a powder metallurgy (P/M) route. Two carbide particle sizes, < 20 µm and 20-32 µm, were mixed with Fe powder. The powder mixtures were compacted and sintered at 3 different temperatures, 1100, 1150 and 1200 °C. Microstructures of sintered Fe-5 wt. % SiC composites showed evidence of SiC decomposition. The decomposed Si and C atoms diffused into Fe particles resulting in formation of solid solution of Si and C in Fe during sintering. During cooling, the solid solution of C in Fe decomposed to pearlite structure (ferrite and cementite (Fe3C) lamellar structure). Microstructures of sintered Fe-5 wt. % TiC composites showed no evidence of TiC decomposition at the investigated sintering temperatures. Because of the reaction between SiC and Fe, tensile strength and hardness of the sintered Fe-SiC composites were higher than those of the sintered Fe. Experimental results showed that strength and hardness of the sintered Fe-SiC composites increased with increasing sintering temperature and with decreasing SiC particle size. In contrast, mechanical properties of the sintered Fe-TiC composites were inferior to those of the sintered Fe. The reason of poor mechanical properties may be attributed to poor bonding between Fe and TiC particles.
Authors: Toru Nagaoka, Hiroyuki Watanabe, Masao Fukusumi, Yusuke Kitamura, Tadashi Mizuno, Genryu Abe, Yoshiaki Morisada, Hidetoshi Fujii
Abstract: Modification of AISI D2 tool steel was conducted by friction stir processing (FSP). Effects of tool rotational speed on microstructural evolution and mechanical properties were investigated. Though coarse primary carbides in the size of 10-50 m were observed before FSP, fine carbides smaller than 20 m and martensitic matrix with fine grains were obtained after FSP. High hardness of over 900 HV, higher than the hardness in conventional D2 tool steel, was achieved under the condition of moderate rotational speed.
Authors: Toru Nagaoka, Yoshihisa Kimoto, Hiroyuki Watanabe, Masao Fukusumi, Yoshiaki Morisada, Hidetoshi Fujii, H.K.D.H. Bhadeshia
Abstract: The surface of body-centred cubic Fe-7Al (mass%) alloy plate was successfully modified by friction stir processing with SiC particles addition. The stir zone with SiC addition had an average grain size of 5.9 μm, smaller than that of 10.1 μm in the stir zone without SiC addition. SiC particles introduced by friction stir processing were converted to fine Fe3AlCx particles by reaction with the ferrite matrix. The hardness near the surface of the stir zone was significantly increased to 351 HV by introduction of particles, compared to the hardness of 200 HV in the stir zone without particles addition. The dispersed particles also contributed to suppression of grain growth of the matrix at elevated temperature.
Authors: K. Iwanaga, Toshihiro Tsuchiyama, Setsuo Takaki
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