The Alloy Carbide Compound Study On Mechanism Of Influence On Tensile Properties Of Low Activation Steel

The application of low activated steel to nuclear fusion cladding structural materials has been due to its remarkable thermal physical and mechanical properties,including low radiation swelling,thermal expansion coefficient,and high thermal conductivity.Nevertheless,when exposed to intense irradiation and high temperatures,these properties will drastically diminish.In this paper,low activation steel is taken as the research object to explore the influence mechanism of alloy carbide precipitation on the microstructure behavior during elongation deformation.Systematic investigation of the correlation between alloy carbide’s precipitation behavior,dislocation behavior,and tensile properties was conducted.The influence mechanism of alloy carbide on the tensile deformation of different grain boundary models was revealed by molecular dynamics.In this paper,nuclear fusion steel with strong magnetic field and high temperature service environment is selected as the base material,and low activation steel is used as the prototype for alloy design and organization regulation.Through testing and characterization,it has been discovered that W,Si and Ta alloy elements can refine grains,thereby encouraging MX precipitation and enhancing the mechanical properties of steel at both room temperature and high temperatures,particularly in regards to elongation.This also enhances the impact toughness and DBTT temperature of the material.The mechanical properties of low activation steels are significantly impacted by the grain size,the quantity and size of precipitates,and so on.In order to investigate the influence of carbide on the deformation behavior of grain boundaries at the atomic scale,this work uses molecular dynamics to simulate the effect of carbide on the deformation mechanism at grain boundaries(Σ5(031))during tensile deformation.The plastic deformation of grain boundaries is mainly dislocation slip and amorphous plastic deformation.The enlargement of carbide size and amount heightens the amorphous plastic’s deformation,hindering dislocation motion,thus leading to a concentration of local structural stress and microcracks.The mechanism of the influence of carbide on the generation and propagation of cracks is elucidated theoretically.