Effect of adding elements on glass-forming ability of (Cu47Ti34Zr11Ni8)99M (MÂ =Â Al, Be, Si, Nb, Fe and Co) bulk amorphous alloys

Bulk amorphous alloys (Cu47Ti34Zr11Ni8)99M (M = Al, Be, Si, Nb, Fe and Co) were prepared by arc melting and suction casting. The effect of the addition of alloying elements on the glass-forming ability and thermal stability of Cu47Ti34Zr11Ni8 was studied. With the addition of Si, the glass-forming ability of the Cu47Ti34Zr11Ni8 alloy is improved, which is evidenced by the increase of supercooled liquid region ΔTx, the reduced glass transition temperature Trg, γ parameter, KH stability parameter. With the addition of Al, Be, Co, Fe and Nb, the glass-forming ability of the alloys is decreased. Calculation of the formation enthalpies of amorphous alloys by using Miedema's theory, show that the glass-forming ability of the (Cu47Ti34Zr11Ni8)99M decreases with increasing formation enthalpy of the amorphous phase except in the case of Cu47Ti34Zr11Ni8. The glass transition activation energy linearly increases with increasing atom size parameter δ.