Morphology of tungsten growth forms in quasicrystalline Al_(65)Cu_(20)Fe_(14)W alloys

摘要

The growth morphology and arrangement of tungsten and β-phase (Al (Fe, Cu)) in Al-Cu-Fe-W alloy were analyzed. The composition of Al_(65)Cu_(20)Fe_(14)W_1 (at.%) was used for preparation of ingots containing the icosahedral quasicrystalline phase. The ingots were obtained in a two-stage process. At the first stage the induction melting of the elements and preliminary homogenization by mechanical mixing were carried out. The second stage was realized by vertical Bridgman technique of directional crystallization. The X-ray phase analysis, optical and scanning electron microscopy (SEM) observations and chemical analysis were performed. It was stated that the whiskers of tungsten were irregularly distributed in the volume of ingots. They often form a clump-like agglomerations. The whiskers have different diameters and length. Minimal diameter of the whiskers was about 10 – 100 nm and maximal – several dozen micrometers. The whiskers of tungsten formed a clump-like frames on which the membrane form of β-phase was stretched out or a non-planar oval forms.