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

F AUDEBERT; P SVEC; M GALANO; F SAPORITI; N ROUNTHWAITE; M FONTANA; G VLASAK; D JANICKOVIC

Simposio; 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 w hich 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 w ith higher microstructural stability. Melt-spun samples of Al94Fe2V4 and Al93Fe3Cr2(TixV1-x)2 (at%) w ith x=0, and 0.5, w ere characterized by X-ray diffraction and transmission electron microscopy. The microstructural transformation against temperature w as analyzed using differential scanning calorimetry, resistometry, dilatometry and heat treatment follow ed 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 tw o steps for the Al-Fe-Cr-Ti alloy. How ever, 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.