Effect of MnS inclusions on plastic deformation and fracture behavior of the steel matrix at high temperature

* Corresponding author. E-mail address: lxg@ysu.edu.cn (X. -g. Liu).,The effect of MnS inclusions on the plastic deformation and fracture behavior of a steel matrix at high temperature was studied. The macroscopic mechanical properties of the material were analyzed using high-temperature uniaxial tensile testing. Numerical simulations were performed by combining the response surface method and finite element simulations. The Gurson-Tvergaard-Needleman damage parameters and the void growth accelerating factor (k) were obtained at different temperatures. Through the fracture analysis and microstructure analysis of the samples at different temperatures, the reasons that affect the macro mechanical properties of the materials are obtained. At 900 degrees C-1200 degrees C, there was a large difference in strength and toughness between steels with and without MnS inclusions. The strength of the materials was determined by both the stress intensification caused by the MnS inclusions and stress softening due to dynamic recrystallization (DRX). The plasticity of the materials was jointly determined by the MnS inclusions promoting void initiation and growth, and the DRX inhibiting void growth and coalescence. Moreover, the accelerating factor of void growth (k) reflected the comprehensive effect of MnS and temperature on the evolution of voids in the matrix.