Interaction coefficients in Fe-C-Ti-i (i = Si, Cr, AI, Ni) systems

Abstract

Ever since Schroeder and Chipman_[10] initiated the application of the silver bath iso-activity method to the study of activity interaction coefficients of components in iron alloys, the method was only applied to some ternary systems in which only one component dissolves in both liquid iron and liquid silver. The authors of the present work proposed a method which enables the silver bath iso-activity method to be utilized to study the activity interaction coefficients of two components simultaneously dissolvable in both liquid iron and liquid silver by establishing an iso-i-j-activity state for several Fe-C-i-j quarternary samples through a common silver bath. This new “quarternary silver bath iso-activity method” was applied to quarternary Fe-C-Ti-i (i = Si,Cr, Al,Ni) melts at 1600 °C and estimated the activity interaction coefficients as follows: ε ^¡_Ti = 7.96, ρ ^¡_Ti = −6.88, ρ ^Ti_si = 0.51, ρ ^Ti,si_Ti = −2.27, ρ ^Ti,si_Ti = −5.66 ε ^ŗ_Ti = 3.46, ρ ^ŗ_Ti = 10.43, ρ ^Cr,Ti_Ti = 17.40 ε ^Al_Ti = 0.93, ρ ^ŗ_Ti = 10.22, ρ ^Al,Ti_Ti = 25.11 ε ^Ni_Ti = 2.49, ρ ^Ni_Ti = 9.33, ρ ^Ni,Ti_Ti = 16.37