A new microstructure model is developed for amorphous alloys,so called Cluster medel, in which the amorphous phase is thought of composing of randomly distributed ordered clusters of different sizes.Thermodynamic calc...A new microstructure model is developed for amorphous alloys,so called Cluster medel, in which the amorphous phase is thought of composing of randomly distributed ordered clusters of different sizes.Thermodynamic calculation on this model deduces a parameter describing the glass forming ability of metallic alloys:α_c=(1-2.08/Φ_m)T_g/T_m,where T_g is gass transition temperature,T_m is the melting temperature,and Φ_m is entralpy change of melting.It is believed that easy glass forming alloy systems have larger values of a_c.This new criterion of GFA not only provides the theoretical background for several GFA criteria in the literature cited,but also can predict the GFA of many alloy systems more reasonably and accurately.展开更多
Classical molecular dynamics(MD)were conducted to study the structure and energy distribution of Zr_(x)Cu_(90-x)Al_(10)(x=20,30,40,50,60,70)ternary alloys.When the Zr composition is 30%,the glass transition temperatur...Classical molecular dynamics(MD)were conducted to study the structure and energy distribution of Zr_(x)Cu_(90-x)Al_(10)(x=20,30,40,50,60,70)ternary alloys.When the Zr composition is 30%,the glass transition temperature reaches the maximum value and the Zr_(30)Cu_(60)Al_(10)owns high glass forming ability(GFA).Analysis of the short⁃range structure shows that there are more low⁃energy Zr⁃centered polyhedron with high coordination number(CN)and Cu and Al⁃centered coordination polyhedron with CN=12 in Zr_(30)Cu_(60_Al_(10)alloy.As the medium⁃range structure is concerned,Zr_(30)Cu_(60_Al_(10)alloy has the largest number of coordination polyhedron connection sharing three atoms and connection in this way presenting the lowest energy.These low⁃energy and stable short and medium⁃range structures contribute to the high GFA of Zr_(30)Cu_(60_Al_(10).展开更多
文摘A new microstructure model is developed for amorphous alloys,so called Cluster medel, in which the amorphous phase is thought of composing of randomly distributed ordered clusters of different sizes.Thermodynamic calculation on this model deduces a parameter describing the glass forming ability of metallic alloys:α_c=(1-2.08/Φ_m)T_g/T_m,where T_g is gass transition temperature,T_m is the melting temperature,and Φ_m is entralpy change of melting.It is believed that easy glass forming alloy systems have larger values of a_c.This new criterion of GFA not only provides the theoretical background for several GFA criteria in the literature cited,but also can predict the GFA of many alloy systems more reasonably and accurately.
文摘Classical molecular dynamics(MD)were conducted to study the structure and energy distribution of Zr_(x)Cu_(90-x)Al_(10)(x=20,30,40,50,60,70)ternary alloys.When the Zr composition is 30%,the glass transition temperature reaches the maximum value and the Zr_(30)Cu_(60)Al_(10)owns high glass forming ability(GFA).Analysis of the short⁃range structure shows that there are more low⁃energy Zr⁃centered polyhedron with high coordination number(CN)and Cu and Al⁃centered coordination polyhedron with CN=12 in Zr_(30)Cu_(60_Al_(10)alloy.As the medium⁃range structure is concerned,Zr_(30)Cu_(60_Al_(10)alloy has the largest number of coordination polyhedron connection sharing three atoms and connection in this way presenting the lowest energy.These low⁃energy and stable short and medium⁃range structures contribute to the high GFA of Zr_(30)Cu_(60_Al_(10).