The Formation Mechanism of Iron Aluminide Phases in Fe-Al System with Different Raw Materials Ratio

In this study, the formation mechanism of iron aluminide phases in the FeAl system with different raw material ratios was investigated. In aluminide systems, full consumption of aluminium or its presence have a major impact on the reaction process, the type of products and the mechanism. However these have not studied and only a defined stoichiometric ratio has been established. Therefore, the current study objective is to determine the effect of raw materials proportion on the reaction mechanism. To achieve this goal, the samples with ratios of 1:3, 1:1 and 3:1 of iron and aluminum were heat treated at 700, 800 and 900ºC. It was found that the first phase formed is Fe_2Al_5. It also proved that the following reaction trend depends on the primary content of iron and aluminum. In the ratio of 3:1 of iron and aluminum, the system tends to achieve the Fe_3Al phase at higher temperatures while in the ratio of 1:1 and 1:3, FeAl is the final product. It also was found that more Al postpones the FeAl formation. In the other words, FeAl can be produced at the lower temperature in the ratio of 1:1 of iron and aluminum in the comparison with the ratio of 1:3.