Fe-V和Fe-Ti熔体的作用浓度计算模型

MODELS FOR CALCULATING MASS ACTION CONCENTRATIONS FOR Fe-V AND Fe-Ti MELTS

根据相图和含化合物金属熔体结构的共存理论推导了Fe—V和Fe—Ti熔体作用浓度的计算模型.计算结果与实测活度值相符,从而证明所制定的模型反映了Fe—V和Fe—Ti熔体结构的本质.与此同时还求得了生成FeV,Fe_2Ti,FeTi和FeTi_2四个化合物在1600℃下的标准生成自由能.

According to the coexistence theory of metallic melt structure involved in compound formation, the symmetric negative deviation of activities of Fe-V melts and the Fe-V phase diagram, the structural units of these melts are determined as Fe, V atoms and FeV molecule. Thus a model for calculating mass action concentrations for Fe-V melts is deduced as N_1+N_2+KN_1N_-1=0, N_2=(1-N_1)/(1+KN_1) aN_1-bN_2+(a-b)KN_1N_2=0 K=(1-(a+1)N_1-(1-b)N_2)/((a-b+1)N_1N_2) aN_1(1+KN_1)+[(a-b)KN_1-b](1-N)=0 Similarly, the structural units of Fe-Ti melts are identified as Fe, Ti atoms and FeTi, Fe_2Ti, FeTi_2 molecules as well. The model for mass action concentrations for Fe-Ti melts consists of N_1+N_2+K_1N_1N_2+K_2N_1~2N_2+K_3N_1N_2~2-1=0 aN_1-bN_2+(a-b)K_1N_1N_2+(2a-b)K_2N_1~2N_2+(a-2b)K_3N_1N_2~2=0 1-(a+1)N_1-(1-b)N_2=(a-b+1)K_1N_1N_2+(2a-b+1)K_2N_1~2N_2+(a-26+1)K_3N_1N_2~2=0 (1-(a+1)N_1-(1-b)N_2)/((2a-b+1)N_1~2N_2)=(a-2b+1)N_2/(2a-b+1)N_1+K_1(a-b+1)/(2a-b+1)N_1 Results of calculation agree well with measured activities, showing that the deduced models reflect the structural characteristics of Fe-V and Fe-Ti melts respectively. The standard free energies of formation of FeV, FeTi, Fe_2 Ti and FeTi_2 at 1600℃ ave determined respectively: △G_(Fev)=-133809 J/mol, △G_(FeTi)~0=-76587J/mol, △G_(Fe_2)~0Ti=-1332711 J/mol, △G_(FeTi_2)~0=-779792J/mol.