(東北大學(xué)材料與冶金學(xué)院，沈陽 110006)
摘 要: 以Miedema二元合金生成熱模型為基礎(chǔ)，結(jié)合一些基本熱力學(xué)關(guān)系式，利用元素的基本性質(zhì)計(jì)算了1073K下Al-Mg合金中組元Mg的活度及合金的部分熱力學(xué)函數(shù)(ΔH，GE，SE)。結(jié)果表明，在1073K下，溶液中Mg的行為相對(duì)拉烏爾定律存在較大的負(fù)偏差；混合焓、過剩自由能與過剩熵在整個(gè)濃度范圍內(nèi)均為負(fù)值；混合焓最小值為-11.4 kJ/mol，過剩自由能最小值為-8.77 kJ/mol，過剩熵的絕對(duì)值較小，接近零。計(jì)算結(jié)果與實(shí)驗(yàn)數(shù)據(jù)吻合較好。
關(guān)鍵字: Al-Mg合金 活度 熱力學(xué)函數(shù)
（School of Materials Science and Metallurgy,Northeastern University, Shenyang 110006, P. R. China）
Abstract:Based on the Miedema's model for calculating the formation heat of binary system, the activity of Mg in Al-Mg alloys and some of the thermodynamic functions (ΔH, GE, SE) at 1073 K of the alloy were calculated by taking use of the basic properties of the elements (electronic negativity φ, electronic density nws, mol volume V). The results indicated that the Mg concentration shows a negative deviation from Rault's Law; mixing enthalpy, excess free energy and excess entropy are all negative in the whole range of concentration; the minimum value of mixed enthalpy is -11.4 k J·mol-1, the minimum excess free energy is -8.77 kJ·mol-1 , the absolute value of excess entropy appoaches zero. The calulated results showed this method is feasible and accord with the experimental data perfectly.
Key words: Al-Mg alloy activity thermodynamic function
