NANOQUASICRYSTALLINE Al-Fe-Cr-BASED ALLOYS. Part I: PHASE TRANSFORMATIONS

M. GALANO, F. AUDEBERT, I. C. STONE AND B. CANTOR

ACTA MATERIALIA

Elsevier

Año: 2009 vol. 57 p. 5107 - 5119

1359-6454

Nanoquasicrystalline Al-Fe-Cr-based alloys composed of icosahedral quasicrystalline particles with sub-micro size embedded in a-Al matrix have higher strength at elevated temperature compared with commercial Al alloys. However, further improvement of the microstructural stability is desirable in order to maximise elevated temperature strength. A detailed study of the effect on the microstructure and the phase transformations by the addition of Ti, V, Nb or Ta to a ternary Al93(Fe3Cr2)7 alloy was carried out using heat treatments and microstructural characterisation. The addition of the fourth element leads to a refined microstructure and can stabilise the icosahedral topology, delaying the quasicrystalline icosahedral phase decomposition until higher temperature. The addition of Nb or Ta enabled a greater stabilisation effect than Ti or V, retaining a microstructure similar to the as-spun state after heat treatment between 450-550°C and even retaining icosahedral particles up to 550°C. The outstanding microstructural stabilisation obtained with addition of Nb or Ta leads to very promising applications in the automotive and aeronautic industries.