• Journal of the Korean Geotechnical Society
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• v.39 no.11
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• pp.33-40
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• 2023

This study explores the performance of pile foundations in highly expansive soil, incorporating magnesium oxide-based refractory materials. A controlled model chamber, housing a fixed pile, was utilized to induce ground expansion through fused magnesia (FM). The investigation focused on measuring the vertical displacement of FM-sand mixtures and the axial load on the pile in relation to depth and time. The study varied the amount of FM content (FM_c) at 30%, 50%, and 70%. The upward movement exhibited an augmentation with increasing FM_c, tapering off with depth as accumulation progressed toward the mixture surface. Compression and tensile forces were both evident along the pile for FM_c at 30% and 50%, while only a tensile force was observed at an FM_c of 70%. These results offer valuable insights for the analysis of pile behavior within FM-sand mixtures.

• Journal of Korea Foundry Society
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• v.35 no.5
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• pp.114-119
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• 2015

This paper reports the effect of a refractory crucible type on the microstructure of duplex stainless steel (DSS) cast with the addition of gadolinium using air-induction melting. Grade 4A DSSs with 1 wt% of gadolinium (Gd) were fabricated in various crucibles including alumina ($Al_2O_3$), magnesia (MgO), calcia (CaO) coated with yttria ($Y_2O_3$) and graphite. The standard free energies of the formation of calcium and yttrium oxide were lower than those of gadolinium oxide and other crucible elements based oxide. The yield of Gd in DSS using $Al_2O_3$, MgO, CaO-coated $Y_2O_3$ and graphite was 5, 19, 83 and 96%, respectively. As Gd yield increased, the amount of Gd-based inclusions increased, the size of the inclusions were reduced, and the inclusions became evenly distributed.