The effect of Zr addition on the structure and high temperature strength of Fe-30 at.% Al type alloys
2012
Abstract
The structure of four Fe-30Al alloys with different contents of Zr has been studied. Light optical microscopy (LOM), scanning electron microscopy (SEM) with EDX module, measurement of microhardness as well as X-ray diffraction (XRD) was used to determine the structure and phase composition.
Addition of Zr to Fe-30Al leads, in the cast state, to the formation of a Fe-Al matrix with a hard lamellar eutectic skeleton. The eutectic is composed of thin lamellae of lambda(1)-Laves phase Zr(Fe,Al)(2) and Fe-Al (B2/D0(3)).
Annealing at 1000 degrees C for 200 h results in the formation of the equilibrium phase tau(1) Zr(Fe,Al)(12). The presence of these phases in the matrix leads to increase of high temperature yield stress and strength.