Phase Transformation in Nanoquasicrystalline Al-Based Alloys

F AUDEBERT; M GALANO

Congreso; ernational Conference on Rapidly Quenched and Metastable Materials; 2008

Nanoquasicrystalline Al-based alloys have high strengths at elevated temperatures what makes them promising materials for applications in the automotive and aeronautical industries. The microstructure is composed of nanoquasicrystalline particles embedded in an α-Al matrix. The metastability of the quasicrystalline phase can limit the use of these alloys at elevated temperatures. In previous work, it was observed that the use of Nb or Ta delayed the microstructural decomposition to higher temperatures [1]. Therefore, it is of great importance to understand the quasicrystalline phase transformation in these systems. In this work, the microstructural transformation of several nanoquasicrystalline Al based alloys had been analysed. In particular, the quasicrystalline phase transformation was studied on a group of melt-spun Al-Fe-Cr based alloys by means X-ray diffraction and in-situ hot-stage transmission electron microscopy (TEM). Additional phase chemical analysis using energy dispersive X-ray spectroscopy in a scanning-transmission electron microscope was performed. Different types of quasicrystalline transformation processes, like dissolution and peritectoide transformation, were observed and will be discussed as a function of the chemical composition.