Point defect behavior in high temperature region in the B2-type intermetallic compound FeAl

A Study of Point Defects in the B2-Phase Region of the Fe-Al System by Mössbauer Spectroscopy

“…According to the literature [3-8, 9, 11], vacancies in the Fe sublattice V Fe are the dominant type of defects in Fe-Al system (maybe organized in triple defects, i.e. two vacancies and an anti-site atom [5,8]). Vacancy formation in Fe-rich Fe-Al alloys has been studied by Schaefer et al [21] using the positron lifetime technique.…”

“…The development of new, more ductile FeAl alloys depends on a thorough understanding of their properties, implicating a better comprehension of the properties and behavior of defect in these materials. Experimental as well as theoretical studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] suggest that point defects in iron aluminides present complex, especially triple defect structure. It is well known that upon rapid quenching from elevated temperatures, iron aluminides retain a high concentration of thermal vacancies, which frozen, increase their yield strength and hardness at room temperature [1][2][3].…”

Interdiffusion in B2 Type Intermetallic Compound FeAl under High Pressures

“…It is impossible to make directly comparison ÁṼ VðN Al Þ with ÁV f ðN Al Þ þ ÁV m ðN Al Þ, because the concentration dependence of ÁV f and ÁV m has not been obtained. However, it has been reported by the in-situ neutron diffraction measurement 3) that the defect concentration in the vicinity of the stoichiometry changes drastically with the variation of concentration; the concentration of Fe-vacancy steadily increases with the increase of Al concentration and reversely, that of anti-site Fe atom on the Al site decreases, while Alvacancies with about 2% exist. These complex changes in the defect concentration probably affect an environment of a diffusing atom and then ÁV f ðN Al Þ and ÁV m ðN Al Þ appear to depend on the concentration.…”

“…Furthermore, it is of great interest to investigate the diffusion behavior, which is expected to be complicated in comparison with pure metals, because their peculiar point defects behavior, which has been actively studied by many workers, [2][3][4][5][6][7] seems to have great influence on the diffusion behavior. Although it has been generally believed that the major structural defects in the FeAl alloys are the anti-site Fe atoms on the Al sublattice (Fe Al ) of the Fe-rich side from the stoichiometric composition and Fe-vacancies (V Fe ) on the Fe sublattice of the Al-rich side, 2) the recent study 3) has shown that four kinds of defect, Fe Al , Al Fe (anti-site Al atoms on the Fe sublattice), V Fe , and V Al (Al-vacancies on the Al sublattice), coexist in the vicinity of the stoichiometry. It has been reported by the positron annihilation measurements, [4][5][6][7] moreover, that the thermal vacancies, that amount has been estimated to be of the order of several percent, change the defect type with increasing temperature.…”

Mössbauer, XRD, and SEM Study of FeAl-Based Powder Alloys with Nanoinclusions

“…Self-propagated high temperature synthesis (SHS) is one of the most prospective methods of powder metallurgy. It is a rapid process that usually leads to the formation of non--equilibrium and nonstoichiometric phases accommodating essential concentration of defects effectively influencing the properties of alloys [1][2][3].…”