摘要
基于Chou模型计算了在1 273 K下Ni-Ti-Si三元合金的形成焓△H、过剩熵SE、过剩吉布斯自由能GE、各组元的活度以及8个Ni-Ti-Si三元合金金属间化合物的形成焓.基于Toop模型预测了在1 273 K下Ni-Ti-Si三元合金的非晶形成范围.结果表明:Ni-Ti-Si三元合金在xNi=0.39、xTi=0.25、xSi=0.36时的△H、SE、GE 取得最小值,分别为△Hmin=-56.25 kJ/mol、SEmin=-6.38 J/mol、GEmin=-48.14 kJ/mol.8 个金属间化合物2中,金属间化合物τ1的△H最负,这说明τ1的相稳定性最高,在凝固时最先析出,然后是τ2、T6、τ8析出,最后是τ3、τ4、τ5析出;Ni-Ti-Si三元系各组元活度值与理想熔体之间存在非常大的负偏差;Ni-Ti-Si三元合金可以形成非晶,并且非晶形成范围很大,主要位于xTi=20％～80％和xNi=15％～90％的成分范围内.本研究计算出的Ni-Ti-Si三元合金的金属间化合物成分范围以及非晶形成范围均与实验结果吻合良好.
Abstract
The formation enthalpy △H,excess entropy SE,excess Gibbs free energy GE,and activity of each constituent element of Ni-Ti-Si ternary alloy at 1 273 K is calculated based on Chou model,and the formation enthalpies of 8 intermetallic compounds of the Ni-Ti-Si ternary alloy are calculated.The amorphous formation range of Ni-Ti-Si ternary alloy at 1 273 K is predicted based on Toop model.The calculated results show that when xNi=0.39,xTi=0.25,and xSi=0.36,the Ni-Ti-Si ter-nary alloy has the minimum △H,SE and GE,and △Hmin=-56.25 kJ/mol,SEmin=-6.38 J/mol,and GEmin=-48.14 kJ/mol.Of the 8 intermetallic compounds,the △H of the intermetallic compound τ1 is the most negative,indicating that its phase stability is the highest.It is the first to precipitate,τ2,τ6,τ7 and T8 are the next,and τ3,τ4 and τ5 are the last.Ni-Ti-Si ternary sys-tem has a very large negative deviation between the activity values of each constituent element and the ideal melt.Amorphous can be formed in the Ni-Ti-Si ternary alloy,and the amorphous formation range is very large,mainly in the composition range of xTi=20％～80％and xNi=15％～90％.The calculated range of intermetallic compounds and amorphous formation range of Ni-Ti-Si ternary alloy are in good agreement with the experimental results.
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