AN INVESTIGATION ON THE MICROSTRUCTURAL STABILITY OF RAPIDLY SOLIDIFIED AL-FE-V-SI ALLOY RIBBON

The thermal stability of the dispersive particles in melt-spun ribbons was studied by differential thermal analysis, X-ray diffraction, ener gy-dispersive X-ray analysis and transmission electron microscopy. The experimental results show that nearly spherical b.c.c. alpha-Al13(Fe, V)3Si dispersoids exist at room temperature. No noticeable growth of t he dispersoids is observed up to 510-degrees-C for 100 h. Polygonal h. c.p. theta-Al2(Fe,V,Si) dispersoids appear when the temperature rises to 650-degrees-C. At 650-degrees-C for 25 h band-shaped (Al,Si)13Fe4 d ispersoids are formed in the specimen and spherical, polygonal and ban d-shaped dispersoids are coexistent. The reason for the fineness and v ery slow growth rate of the dispersoids and the role of V atoms in the phase transformation are discussed.