Formation, microstructure and mechanical properties of Al-Fe base quasicrystalline alloys

An icosahedral (I) phase in coexistence with Al-phase was formed in the siz e fraction range up to 125 mum of atomized Al93Fe3Cr2Ti2 powder. The decomp osition temperature of the I-phase is about 790 K. As per energy dispersive X-ray spectroscopy analysis, the constituent composition of the I-phase is Al84.2Fe7.0Cr6.3Ti2.5. It is found that the Al84.2Fe7.0Cr6.3Ti2.5 alloy fo rms a mostly single I-phase in the melt-spun state. Bulk I-alloys in a rod form were produced by extrusion of the atomized powders at 673 K and an ext rusion ratio of 10. The extruded Al93Fe3Cr2Ti2 alloys have good mechanical properties, i.e., sigma (0.2) of 550 MPa, sigma (UTS) of 660 MPa and epsilo n (p) Of 4.5% at room temperature and sigma (0.2) of 330 MPa, sigma (UTS) o f 350 MPa and epsilon (p) Of 1.5% at 573 K. The I-based Al93Fe3Cr2Ti2 alloy is expected to be useful as a new type of high-elevated temperature streng th material. (C) 2000 Elsevier Science B.V. All rights reserved.