Effect of liquidus temperature depression on glass forming ability criteria for La-Al-(Cu,Ni) alloys

Criteria for evaluating the glass forming ability of La-Al-(Cu,Ni) alloys, e.g., the extent of the supercooled liquid region ΔTx (ΔTx = Tx − Tg, Tg is glass transition temperature, and Tx is the onset temperature of the first crystallization event), the reduced glass transition temperature Trg (Trg = Tg/Tl, Tl is the liquidus temperature), the apparent activation energy of the first crystallization peak Ep1, and γ (γ=Tx/(Tg+Tl)) etc., were studied. The criteria were categorized into Tl related and Tl not related ones. The Tl related criteria, such as Trg and γ, etc., generally use the values of Tl measured by DSC (or DTA) heating. They will be depressed to different extent with varying compositions during non-equilibrium cooling, especially for bulk glass forming alloys. This paper suggests to use the solidification temperature Ts instead of Tl.