Nanoquasicrystalline Al-Fe-Cr-based alloys. Part I: Phase transformations

MARINA GALANO; FERNANDO AUDEBERT; IAN STONE; BRIAN CANTOR

ACTA MATERIALIA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2009 vol. 57 p. 5107 - 5119

1359-6454

Nanoquasicrystalline Al?Fe?Cr-based alloys composed of sub-micro-sized icosahedral quasicrystalline particles embedded in a-Al matrix have a higher strength at elevated temperature compared with commercial Al alloys. However, further improvement of the microstructural stability is desirable in order to maximize the 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 treatment and microstructural characterization. The addition of the fourth element leads to a refined microstructure and can stabilize the icosahedral topology, delaying the quasicrystalline icosahedral phase decomposition until a higher temperature is reached. The addition of Nb or Ta enabled a greater stabilization effect than the addition of Ti or V, retaining a microstructure similar to the as-spun state after heat treatment between 450 and 550 C and even retaining icosahedral particles up to 550 C. The outstanding microstructural stabilization obtained with addition of Nb or Ta leads to very promising applications in the automotive and aeronautic industries.