Enthalpy of formation of B2-Fe1−x Al x and B2-(Ni,Fe)1−x Al x

Abstract

The enthalpy of formation of the ordered B2 phases in the Fe-Al and Fe-Ni-Al systems was measured with very good accuracy using a special, laboratory-built differential-solution calorimeter. The measurements were performed at 1073 K as a function of composition, with an accuracy of about 1 pct. The enthalpy of formation of B2-FeAl is most negative for the composition Fe 0.50 Al 0.50 (Ϫ36.29 kJ/ mol). Compounds with Al contents less than about 40 at. pct show a deviation from the linear dependence of the enthalpy of formation with composition which prevails for Al contents larger than 40 at. pct. Upon replacing Fe by Ni while maintaining a constant Al content, the enthalpy of formation of B2-(Fe,Ni)Al compounds becomes more negative. With decreasing Al content and for a constant Fe/Ni ratio, the enthalpy of formation of the ternary phase becomes less negative.

Thermodynamic investigation of the A2/B2 region of the Fe-Al system by Knudsen effusion mass spectrometry

“…The results for the integral molar enthalpy of mixing, in general, agree very well with the quantities of Breuer et al [13] The "V" shape of the function, which is characteristic for ordered compounds, can evidently be seen from our results.…”

“…Various types of calorimetric measurements of the mixing enthalpy have been made, [8][9][10][11][12][13][14] as have measurements of the Al chemical potential by electromotive force methods [15,16] and by an isopiestic vapor-pressure method. [17] Ichise [18] first used the Knudsen effusion mass spectrometric (KEMS) method in an investigation of the A2 region at 1673 K. Later, a KEMS investigation of 10 different alloy compositions (between 9.7 and 65.6 at.…”

Stability and electronic structure of the complexK2PtCl6-structure hydridesDMHalilov1, Singh2, Gupta3 et al. 2004Phys. Rev. B376180View full textAdd to dashboardCite

“…The result was -77 kJ/mol(FeAl), which is in good agreement with the experimental value of -72.6 kJ/mol. 30,40 This suggests that the error in the formation energy of FeBe 2 is likely in the range of 5 kJ/mol.…”

Use of Recycled Steel Machining Chips and Aluminum Can Shreds for Synthesizing Iron Aluminide Intermetallic Alloys

“…2(b), the temperature decrease stopped at the similar temperature due to solidification of FeAl. The exothermic reactions seem to be useful for the energy saving in the production process of the iron aluminide intermetallic alloys, but their contribution may not be dramatic because the formation enthalpies of Fe 3 Al and FeAl are not very large; they are 24 and 36 kJ/mol, 15) respectively.…”