Thermal Stability and Microstructural Evolution in V Containing Nanoquasicrystalline Al-Based Alloys

F. AUDEBERT, P. SVEC, M. GALANO, N. ROUNTHWAITE, F. SAPORITI, M. FONTANA, G. VLASAK AND D. JANICKOVIC

Buenos Aires, Argentina

Conferencia; XV International Symposium on Metastable and Nano Materials” (ISMANAM 2008); 2008

Nanoquasicrystalline alloys from Al-Fe-V and Al–Fe–Cr–Ti systems have a microstructure containing quasicrystalline icosahedral particles embedded in an Al matrix. These alloys exhibit higher strength at elevated temperatures than the Al commercial alloys which make these alloys very promising for industrial application at elevated temperature. As the quasicrystal phase in these systems is a metastable phase, it is very important to understand the phase transformation process in order to develop nanoquasicrystalline alloys with higher microstructural stability. Melt-spun samples of Al94Fe2V4 and Al93Fe3Cr2(TixV1-x)2 (at%) with x=0, and 0.5, were characterized by X-ray diffraction and transmission electron microscopy. The microstructural transformation against temperature was analyzed using differential scanning calorimetry, resistometry, dilatometry and heat treatment followed by XRD analysis. The dilatation coefficient of the alloys studied appears to be a bit higher than the corresponding to the Pure Aluminium. The transformation of the quasicrystalline phase to the stable crystalline phases is observed occurs in two steps for the Al-Fe-Cr-Ti alloy. However, for the V containing ternary alloy the transformation of the quasicrystalline phase occurs in one step and at higher temperature than for the Al-Fe-Cr-Ti alloy