Effect Of Irradiation On The Hardness And Microstructure Of Fe-Ni-Si Ternary Alloy

Reactor Pressure Vessel(RPV)steel is one of the important barriers to ensure the safe and stable operation of nuclear power plants.Studying the behavior of alloying elements during the irradiation process has important guiding significance for the development of a new generation of RPV steel.In this paper,a simple ternary alloy FeNi-Si is used as the research object.Using nanoindentation technology,atom probe tomography(APT),transmission electron microscope(TEM),we systematically study the effect of irradiation temperature(RT,250 ?,350 ?)and irradiation dose(0.1 dpa,0.6 dpa,1.5 dpa)on the hardness and microstructure of the material.The changes in the nanoindentation hardness of the material before and after irradiation are analyzed.The effect of different irradiation doses and irradiation temperature on the spatial distribution of solute atoms,the characteristics of dislocation loops formed under different irradiation temperatures and the effects of irradiation temperature on the segregation of elements on large-angle grain boundaries are discussed.The research results show that: irradiation will increase the hardness of the material,and with the increase of the irradiation dose and temperature,the hardness of the material will also increase;after irradiation,many Ni-Si nano-solute clusters are produced in the material;under low-temperature irradiation(RT,250?),with the increase of the irradiation dose,the number of solute clusters increases,but the clusters are small in size and do not grow up;under medium-temperature irradiation(350?),with the increase of the radiation dose,the number of solute clusters increases,but at1.5 dpa,the cluster size becomes larger;as the size of the cluster increases,the proportion of Si in the cluster gradually increases,indicating that Si plays an important role in cluster growth;irradiation dislocation loops are small at room temperature,and a large number of linear dislocation loops appear at 350 ?;as the irradiation temperature increases,the concentration of Ni and Si on the grain boundary increases,and the concentration of C is the highest at room temperature.