Calculations of mixing enthalpy and mismatch entropy for ternary amorphous alloys
Calculations of mixing enthalpy and mismatch entropy for ternary amorphous alloys
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DOI：
10.2320/matertrans1989.41.1372
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发表时间：
2000-11-01
期刊：
影响因子：
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通讯作者：
Inoue, A
中科院分区：
文献类型：
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作者：
Takeuchi, A;Inoue, A
利用热力学函数计算了351种三元非晶体系中6450种合金总数的化学混合焓（DeltaH(Chem)）和玻尔兹曼常数归一化的失配熵（S-sigma/k(B)）对应于实现高非晶成形能力（AFA）的三个经验规律。三元非晶合金的δ tah （chem）为-86 ~ 25 kJ/mol， S-sigma/k(B)为1.8 × 10(-3) ~ 5.7。δ tah （chem）和S-sigma/k(B)的平均值分别为-33 J/mol和0.33。9种三元非晶体系中的30种合金，其中Ag-Cu-Fe体系中的10种合金的δ tah （chem）值均为正值。在δ tah (chem) - log（S-sigma/k(B)）图中，除含H、含c合金、Si-W-Zr体系和δ tah （chem）为正值的32条合金外，大多数三元非晶合金在梯形区域内均有δ tah （chem）和S-sigma/k(B)值。对典型的五种三元非晶体系进行了AFA分析。得到以下四个结果。1)根据三个经验规律的概念，Al-La-Ni和B-Fe-Zr合金具有较高的AFA。2) Al-B-Fe合金中合金成分的进一步增加导致其AFA增大。3)以熔化温度和熔化温度下粘度为代表的热力学因素是评价镁、钯基非晶合金AFA的必要条件。4)在每种合金体系中，log（S-sigma/k(B)）随δ tah （chem）的减小而增大，这表明非晶相相对于固溶体和中间相具有稳定化的趋势。
Chemical mixing enthalpy (DeltaH(Chem)) and mismatch entropy normalized by Boltzmann constant (S-sigma/k(B)) corresponding to the three empirical rules for the achievement of high amorphous-forming ability (AFA) were calculated with thermodynamical functions for the gross number of 6450 alloys in 351 ternary amorphous systems. The ternary amorphous alloys have DeltaH(chem) Of -86 to 25 kJ/mol and S-sigma/k(B) of 1.8 x 10(-3) to 5.7. The average values of DeltaH(chem) and S-sigma/k(B) are calculated to be -33 J/mol and 0.33, respectively. The 30 alloys in 9 ternary amorphous systems including 10 alloys in Ag-Cu-Fe system have positive values of DeltaH(chem). Most of the ternary amorphous alloys have the values of DeltaH(chem) and S-sigma/k(B) inside a trapezoid region in DeltaH(chem) - log(S-sigma/k(B)) chart except mainly for the H- and the C-containing alloys, Si-W-Zr system and the 32 alleys having positive values of DeltaH(chem). The analysis of AFA was carried out for typical five ternary amorphous systems. The following four results are derived. 1)Al-La-Ni and B-Fe-Zr alloys have high AFA in accordance with the concept of the three empirical rules. 2) The further multiplication of alloy components causes an increase in the AFA of Al-B-Fe alloys. 3) Thermodynamical factors represented by melting temperature and viscosity at the melting temperature are required for evaluation of AFA for Mg- and Pd-based amorphous alloys. 4) A tendency for log(S-sigma/k(B)) to increase with decreasing DeltaH(chem) is recognized in each alloys system, implying the stabilization of an amorphous phase against solid solution and intermediate phase.