X-ray Estimation of Residual Stress Carbide in Carbon Steel T8

Residual stresses of ferrite and cementite phases in globular and lamellar structure carbon steel T8 with tensile plastic deformations were investigated with XRD.For globular structure specimens,the X-ray stress measurement of cementite was carried out,the compressive and the tensile residual stresses in cementite were observed in ferrite.The residual stress in cementite increased with exerted plastic strains till the border strain point and decreased thereafter.The SEM analysis indicated that the crack in the cementite particle and the crack at the boundary between cementite particle and matrix might low the residual stresses in cementite phase.In order to well understand the interaction between cementite and matrix,the plastic strains of two phases and the misfit of plastic strains between them were analyzed based on the Eshelby/Mori-Tanaka model.