Phase and Thermal Stability Analysis of Al-Fe-V-Si-Y Alloys After Solidification at Intermediate Cooling Rates

摘要

Samples of RS-8009 (Al-Fe-V-Si alloy) prepared by both copperrnmold chill casting and rapid solidification processing werernanalyzed using SEM and TEM methods including CBED, selectedrnarea electron diffraction (SAD), and electron backscatterrndiffraction (EBSD). Diffraction analysis revealed a hexagonalrnphase identified as h-AlFeSi (P6/mmm a=2.45 nm c=1.25 nm)rnwith evidence of a structural relationship to the icosahedralrnquasicrystalline (QC) phase and a further relationship with the α-rnAl-Fe-Si phase (Im3¯ a=1.26 nm), which is the desirablernintermetallic in this system and also a quasicrystal approximant.rnThe analysis confirmed the findings of earlier studies on thernsystem, which suggested the same structural relationships usingrndifferent methods. As will be shown, both phases form across arnwide range of cooling rates and appear to have good thermalrnstabilities.