Cu-Zr-Ti系Cu基块体非晶合金的形成和成分优化

利用与团簇相关的变电子浓度判据研究了过渡金属Cu-Zr-Ti系中Cu基块体非晶合金的形成区域和成分特征.据此判据在Cu-Zr-Ti系相图中确定出三条特殊的成分线，(Cu_9／13Zr_4／13)_100-xTi_x，(Cu_0.618Zr_0.382)_100-xTi_x和(Cu_0.56Zr_0.44)关键词：块体非晶合金Cu-Zr-Ti合金原子团簇电子浓度

Formation and composition optimization of Cu-based bulk metallic glasses in Cu-Zr-Ti ternary system

The present paper investigates the formation and composition characteristics of Cu-based bulk metallic glasses (BMGs) in the inter-transition metal system Cu-Zr-Ti by using an “e/a-variant criterion” which is relevant to clusters. Three such composition lines, (Cu_9/13Zr_4/13)_100-xTi_x, (Cu_０.618Zr_０.382)_１００-xTi_x and (Cu_０.56Zr_０.4４)_100-xTi_x, are defined in the Cu-Zr-Ti system. Among them, Cu_９Zr₄, Cu_61.８Zr_38.2 and Cu₅₆Zr₄₄ are specific Cu-Zr binary cluster compositions. Alloy compositions are designed along these three composition lines, and alloy rods with diameter of 3mm are prepared by copper mould casting. X-ray and TEM analysis show that BMGs are formed within Ti content range of x=7.5%—15%, x=7.5%—12.5% and x=5%—12% respectively along these three lines. Thermal analysis results further indicate that these BMGs have igher thermodynamic T_g,T_x,T_g/T_l and γ values, and these values of BMGs on every composition line decrease with increasing Ti content. The optimum BMG composition in this system is Cu₆₄Zr_28.５Ti_7.5 on the (Cu_９/13Zr_4/13)_１00-xTi_x series, which also has the highest hardness and activation energy of crystallization. The characteristic parameters of this BMG are T_g＝736K, T_x＝769K, T_g/T_l=0.627,γ=0.403, H_ν= 6.74GPa and ΔE=3.88 eV, which are all superior to those of the reported BMG Cu_6０Zr_3０Ti_１０.