Razieh Khoshhal, Seyed Vahid Alavi Nezhad Khalil Abad,
Volume 20, Issue 1 (March 2023)
Abstract
- In this article, the effect of graphite on iron-silicon interactions was investigated. It was found that, as graphite enters the iron structure, it permits further development of iron-silicon reactions. It was found that in the stoichiometric ratio of 1:0.5 of iron and silicon, when graphite is added to the system, simultaneously with the reaction of iron and silicon to form Fe3Si5, some amount of carbon can be dissolved in the iron and lead to more diffusion in iron and more iron silicide production. Silicon also reacts with carbon and produces SiC. The more amount of carbon entered into the system, the more growth of SiC occurs, while the production of other iron silicide phases, namely FeSi and Fe3Si preceded. Finally diffused carbon into the iron reaches a definite amount that can form Fe3C. In the stoichiometric ratio of 1:1 of iron and silicon, the formation of FeSi and SiC phases is observable. At the same time, the diffusion of carbon occurs in the same as the previous stoichiometric ratio. In the stoichiometric ratio of 1:2 of iron and silicon, compared with the stoichiometric ratio of 1:1, a larger amount of silicon is available and, the FeSi2 phase can form in addition to FeSi
Razieh Khoshhal, Seyed Vahid Alavi Nezhad Khalil Abad,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
This study utilized aluminum, copper powder according to the stoichiometric ratio of Al₂Cu, and calcium powder in relation to the eutectic composition of Al-Ca at the ratio of 5.5 atomic percent. Two samples were prepared, one without calcium and another with calcium, and were analyzed to determine the impact of calcium on the formation of copper aluminide. Samples were subjected to thermal treatment at temperature of 400, 600, and 800ºC. The obtained results indicated that disappearance of Al₂Cu phase at 800ºC in calcium-free sample and existence of Al₂Cu phase in calcium sample indicating a possible role of calcium in stabilization of Al₂Cu phase. Furthermore, it was concluded that calcium influences phase formation. There was higher diffusion of aluminum in to copper resulting in formation of Al₄Cu₉ not only in the sample with calcium, but also in calcium-free sample. One more finding of the research is that calcium influences microstructure and its homogenization as well. In particular, it was found that calcium-containing sample has the least number of pores and was uniform in the structure.
