The Bond Parameter Function-Formation Enthalpy Model Of The Amorphous Alloys Forming Ability

Amorphous alloys have attracted great interest in aerospace and biomedical applications due to their excellent mechanical properties,good corrosion resistance and excellent biocompatibility.The demand for amorphous alloys with high amorphous forming ability is increasing.Experimental preparation is a direct way to obtain amorphous alloys,and the amorphous alloys with high amorphous forming ability need to be obtained through continuous trial and error.Blind"trial and error"is time-consuming and laborious.The prediction of the amorphous forming range is of great significance for the preparation of amorphous alloys.In this paper,a new theoretical model composed of bond parameter function and amorphous formation enthalpy is proposed.The model was used to study the forming ability of 15 rare earth metals（La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu）based binary amorphous alloys.The results show that the elements that can form an amorphous alloy with rare earth metals are regularly distributed on the two-dimensional D-G diagram and an elliptic curve_d2^（x-m）2+_e2^（y-n）2=1can be used to distinguish the amorphous forming regions and non-forming regions.The related parameters m,n,d and e of the elliptic curve are analyzed,and the positive correlation between them and the physical parameters of the constituent elements is obtained.We propose that if a amorphous alloy with experimental data falls within the ellipse,the amorphous alloy should be in the correct region,otherwise it is incorrect.According to this criterion,the reliability of the bond parameter function-formation enthalpy model for the 15 rare earth metals（La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu）was calculated,giving an overall reliability of 90%.The bond parameter function-formation enthalpy model was used to study the amorphous forming ability of the ternary Ti-based amorphous alloys Ti-Ni-Zr,Ti-Cu-Zr and Ti-Cu-Hf.Each point on the two-dimensional D-G diagram represents a component and all points cover the entire composition range.The results show that the component which can form amorphous alloy are regularly distributed on the two-dimensional D-G diagram.An elliptic curve is used to distinguish the amorphous forming region and non-forming region,the amorphous forming range is predicted.The prediction results of this paper are in good agreement with the experimental data and the accuracy rate is91.9%.The prediction ranges of this paper were compared with experimental data and the prediction ranges of the subregular model.The results show that the prediction results in this study are more accurate than those of the subregular model and can provide better theoretical references for experimental preparation.