Microstructure and mechanical properties of Fe3Al-based alloys with strengthening boride precipitates

Five quaternary Fe-Al-B-M (M = Ti, Hf, Zr, V, W) alloys based on Fe3Al with strengthening boride precipitates were produced by vacuum induction melting. The alloys were investigated with respect to their microstructure and mechanical behaviour up to 1000 degrees C. The mechanical properties were determined by tensile tests, 4-point-bending tests, high-temperature compression tests up to 1000 degrees C as well as creep tests at 650 and 750 degrees C. Microstructural and phase analysis were carried out by light optical microscopy, scanning electron microscopy, X-ray diffraction analysis and differential thermal analysis. The alloys were tested in the as-cast state, after homogenisation at 1200 degrees C for 48 h and after annealing at 800 degrees C for 624 h. Compared to a corresponding binary alloy the examined alloys exhibit significantly improved mechanical high-temperature properties as well as stable microstructures without considerable loss of ductility. (c) 2007 Elsevier Ltd. All rights reserved.