Investigations on Grain Boundary Segregation Energy of Phosphorus in 12Cr1MoV Steel Under Elastic Stress

Abstract

Grain boundary (GB) concentration of P in 12Cr1MoV steel after aging for 15 h under elastic stress of 30 MPa is found to be nearly equal to its initial thermal equilibrium level, which confirms that elastic stress affects thermal equilibrium segregation slightly. By the model and formulation between elastic stress and segregation Gibbs energy, the effect of elastic stress on GB segregation thermodynamics of P is calculated to be slight. The consistency between experiment and calculation gives direct evidence to the validity of the model and formulation.

C‐Type Relationship between Critical Time and Evaporation Parameter for Surface Segregation in the Case of Evaporation

“…Many researchers reported obvious evaporations of atoms segregated on surfaces but did not give complete kinetics . In addition, researchers focused on multicomponent systems and the interactions between different species cannot be excluded easily to agree with the present model for the binary system . At the same time, a set of parameters (surface layer thickness d , diffusion coefficient D , evaporation parameter E , surface concentration C s , enrichment ratio α , maximum surface concentration , bulk concentration C b , critical time t c , balanced surface concentration , environmental pressure P , vapor pressure of solute atoms P i , activity coefficient of solute atoms in surface layer γ i , and saturated vapor pressure of pure solute P i * ) are necessary before fitting and seldom solute atoms have all data in the literature.…”

“…[10,19] In addition, researchers focused on multicomponent systems and the interactions between different species cannot be excluded easily to agree with the present model for the binary system. [20][21][22] At the same time, a set of parameters (surface layer thickness d, diffusion coefficient D, evaporation parameter E, surface concentration C s , enrichment ratio α, maximum surface concentration C max s , bulk concentration C b , critical time t c , balanced surface concentration C ba s , environmental pressure P, vapor pressure of solute atoms P i , activity coefficient of solute atoms in surface layer γ i , and saturated vapor pressure of pure solute P i *) are necessary before fitting and seldom solute atoms have all data in the literature. From extensive literature surveys, the experimental results of the surface segregation of Mg in Al-0.8 wt% Mg alloy studied by Lea and Molinari [23] are suitable to confirm the C-type law.…”