The Al-Cr-Fe system-phases and phase equilibria in the Al-rich corner

An isothermal section for the Al-Cr-Fe system at 1000 degrees C has been experimentally determined. From metallography, electron microprobe analyses and X-ray investigations on quenched samples the phase equilibria in the Al-rich corner of this system were established. No ternary intermetallic phases were found. But the binary compounds-and here especially those intermetallic phases originating in the Al-Cr subsystem-have large solid solubility ranges for the third element. This has a marked influence on the lattice constants, which were determined for all phases. In addition two X-ray spectra are presented. One for Al8Cr5, where three quarters of Cr can be substituted by Fe and for Al4Cr, which was found to have a different crystallographic structure than described elsewhere.