Experimental study of the Be–Si phase diagram

摘要

Wang et al. [1] reported that minor addition of Be in thenas-cast Al-11Si-0.3Mg alloy (wt.%) causes faster precipitationnand more heat effect of metastable βnu0002 than thenalloy without addition of Be and considerably increasesnthe peak hardness achieved during as-cast aging. Both Yinnet al. [2] and Yie et al. [3] have found that the addition ofnBe into commercial Al alloys, such as Al-4.93Si-1.4Fe-n0.63Mg-1.45Cu [2] and Al-11.1Si-1.03Fe-0.08Ti alloysn[3], is beneficial for the transformation of the needleshapedniron-rich phase into the Chinese scripts. It is generallynbelieved that the needle-shaped iron-rich phase isnharmful to the strength and ductility of materials. Theninfluence of Be addition on the quasicrystal-forming abilitynin Al-based alloys, such as alloys in the Al–Cu–Fenand Al–Mn systems, has been investigated [4]. It wasnfound that Be addition modified the icosahedral phasen(i-phase) formation mechanism from peritectic reactionnto primary solidification and resulted in the increase ofnthe volume fraction for the i-phase [4]. In addition, thensubstitution of Al by Be was found to reduce significantlynthe critical Mn content and cooling rate necessarynfor the formation of i-phase [4]. Chen et al. [5]ndemonstrated that the partial substitution of Al by Sinin Al80Mn20 (at.%) binary alloy completely suppressesnthe formation of a pentagonal quasicrystalline T-phasenand drastically modifies the microstructure of the i-phase.nConsequently, knowledge of the phase diagram and thermodynamicnproperties in the Be–Si system is of fundamentalnimportance for guiding the design and processingnof Al-based quasi-crystal materials and multi-componentncommercial Al alloys.