Effect of Si addition on glass forming ability and thermal stability of Al–Fe–La alloys

The effect of Si substitution for Al on the glass forming ability (GFA) and thermal stability of melt-quenched Al88−xFe6La6Six (x = 0, 0.5, 1–4) alloys has been investigated systematically by using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and viscometer. Results show that the addition of Si enhances the thermal stability and GFA of Al–Fe–La alloys, and the alloy containing 1 at.% Si has the best thermal ability, but the GFA of which is not best, the alloy containing 2 at.% Si has the best GFA. However, when Si content is beyond 2 at.%, the addition of Si reduces the GFA and thermal stability of the alloys. It is also found that the addition of Si influences the crystallization behaviors of the alloys, transforming from two-step crystallization process to three-step crystallization process.