Conventional method for simulation of nitriding process and induced stress
This paper motivates to present conventional methods of evaluating volumetric dilatation due to gas nitriding and of elastic-plastic stress considering the fact that the process is limited in the very thin layer near substrate surface. One dimensional diffusion equation is solved to know the nitrogen concentration after some incubation time, where nitrogen atoms diffuse as interstitials ina-iron followed by the compound formation process. Some part of diffused nitrogen converted to form nitrides, such as and others are inverted metallic compounds, such as γ-Fe4N. Fe2N and other MxNy . with Fe and other alloying elements. In the former case, diffused nitrogen itself enlarges the lattice parameter, and the nitrides induce the volumetric dilatation, both of which gives the intrinsic, or initial strain in the body. A conventional stress estimation method is proposed in the framework of total strain theory under the consideration that stress equilibrium equation and strain compatibility condition lead to the non-zero stress and strain in plane without shear stress and strain. If simple elastic-plastic stress-strain constitutive relation is assumed, the stress/strain profile along the depth direction is easily obtained to avoid complicated numerical calculation.
Diffusion of nitrogen Stoichiometry of compound formation Volumetric dilatation Total strain theory Profiles of nitrogen and stresses
Tatsuo Inoue
High-Tech Research Center for Structure and Material Development, Fukuyama University, Fukuyama, Japan
国际会议
北京
英文
833-836
2012-10-23（万方平台首次上网日期，不代表论文的发表时间）