Thermophysical properties of FeAl (Fe-40 at.%Al)

The thermophysical properties - electrical resistivity. thermal conductivit y, thermal expansion, and specific heat, of a B2 iron-aluminide (Fe-40 at.% Al) alloy are measured. The measured values of electrical resistivity indi cate three distinct regions. An initial sharp rise below 400 degreesC is fo llowed by a gradual increase to near saturation around 900 degreesC. Resist ivity above this temperature exhibits an anomalous negative temperature dep endence. The thermal conductivity displays a continuous rise as a function of temperature for T < 800<degrees>C, beyond which it saturates to a value of similar to0.17 W/cm-degreesC. The relation between electrical resistivit y and thermal conductivity obeys the Wiedemann-Franz law signifying the dom inance of electrons in the heat transport. The measurements of specific hea t indicate a complex behavior suggesting inseparable contributions of vario us temperature dependent phenomena arising from phonons. conduction electro ns and magnons. Both the thermal expansion and mean coefficient of thermal expansion (MCT) exhibit a rising trend with temperature. The temperature de pendence of the various modes of lattice, electronic, and magnetic excitati ons is invoked to csp]ain the observed variations in properties. The role o f the inherent electronic and magnetic structure on physical properties is highlighted. (C) 2000 Elsevier Science Ltd. All rights reserved.