Author
Mel I. Mendelson
Bio: Mel I. Mendelson is an academic researcher from Fairchild Semiconductor International, Inc.. The author has contributed to research in topics: Crystallite & Grain boundary diffusion coefficient. The author has an hindex of 1, co-authored 1 publications receiving 1597 citations.
Papers
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TL;DR: In this article, the average grain size of a log-normal distribution of grain sizes with tetrakaidecahedral shape is related to the average intercept size by a proportionality constant.
Abstract: A model is proposed which realistically characterizes the grain structure of polycrystalline ceramics. The average grain size of a log-normal distribution of grain sizes with tetrakaidecahedral (truncated octahedral) shape is related to the average intercept size by a proportionality constant. This result can be used to determine the average grain size of a sintered powder compact composed of nontextured grains which shows no discontinuous grain growth.
1,732 citations
Cited by
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TL;DR: In this article, a numerical model is presented for the prediction of grain size in inoculated castings and is tested against measured grain sizes obtained in standard grain-refiner tests on aluminium alloys.
870 citations
731 citations
TL;DR: In this article, a systematic study of various spark plasma sintering (SPS) parameters, namely temperature, holding time, heating rate, pressure, and pulse sequence, was conducted to investigate their effect on the densification, grain-growth kinetics, hardness, and fracture toughness of a commercially available submicrometer-sized Al 2 O 3 powder.
Abstract: A systematic study of various spark plasma sintering (SPS) parameters, namely temperature, holding time, heating rate, pressure, and pulse sequence, was conducted to investigate their effect on the densification, grain-growth kinetics, hardness, and fracture toughness of a commercially available submicrometer-sized Al 2 O 3 powder. The obtained experimental data clearly show that the SPS process enhances both densification and grain growth. Thus, Al 2 O 3 could be fully densified at a much lower temperature (1150°C), within a much shorter time (minutes), than in more conventional sintering processes. It is suggested that the densification is enhanced in the initial part of the sintering cycle by a local spark-discharge process in the vicinity of contacting particles, and that both grain-boundary diffusion and grain-boundary migration are enhanced by the electrical field originating from the pulsed direct current used for heating the sample. Both the diffusion and the migration that promote the grain growth were found to be strongly dependent on temperature, implying that it is possible to retain the original fine-grained structure in fully densified bodies by avoiding a too high sintering temperature. Hardness values in the range 21-22 GPa and fracture toughness values of 3.5 ± 0.5 MPa.m 1/2 were found for the compacts containing submicrometer-sized Al 2 O 3 grains.
729 citations
TL;DR: In this paper, the percolation of the carbon nanotubes was studied and discussed in relation to the nature of the matrix, the electrical conductivity, the fracture strength and the fracture toughness.
530 citations
TL;DR: In this paper, a series of exposure tests was carried out with anode substrates used in SOFC development at the Research Centre Julich, where the changes in electrical conductivity as well as in the microstructure of the material were investigated.
457 citations