Phase Transformation in a Rapidly Solidified Al-83Fe-19V-21Si Alloy

Al-Fe-V-Si alloys can be rapidly solidified and consolidated by means of hot isostatic pressing and extrusion to produce the structures which contain very small iron aluminide precipitates, thereby opening a new avenue to the design of advanced aluminum alloys with a larger volume fractions of iron aluminide precipitates Such alloys possess high strength at elevated temperatures The purpose of the present study is to examine the formation of the iron aluminide phase and the thermal stability of rapidly solidified Al-83Fe-19V-21Si The Al-83Fe-19V-21Si alloy was rapidly solidified from the melt, the molten droplets formed by gas atomization being quenched in high velocity water on a rapidly-rotating copper wheel The average diameter of powder was about 17μmThe phases present in as-rapidly solidified Al-83Fe-19V-21Si alloy powders and the phase transformation during heating were investigated by using scanning electron microscope, X-ray diffraction and differential thermal analysis The results show that the microstructures of as-rapidly solidified powders consist of α(Al) and Al13 (Fe,V)3 Si phases The addition of V to the Al-Fe-Si system is essential to stabilize the metastable Al13Fe3Si phase that is otherwise susceptible to coarsening at moderately elevated temperature At temperatures between 638℃ and 645℃, the cubic Al13 (Fe, V)3Si phase transforms to the hexagonal Al3 (Fe, V, Si) phase