Effect of irradiation on mechanical properties structure and swelling of steels 1Kh18N10T and 0Kh16N15M3B

The effect of the neutron irradiation on mechanical properties, structure and swelling of the 1Kh18N10T and 0Kh16N15M3B steels, previously hardened by cold deformation and thermomechanical treatment, has been studied. The irradiation were performed in a BR-5 reactor by integral neutron fluxes 2.6x1021n/cm2 and 1x1022n/cm2 at 450-500 deg C. The mechanical characteristics were determined at temperatures of 300 and 550 deg C. Metallographic studies were carried out with the tensile test specimen heads. The porosity value were calculated by electron-microscopic pictures. The mechanical tests of steels before irradiation has shown that with an increase in the degree of the cold deformation the yield limit of the 1Kh18N10T steel continuously increases at the test temperature of 300 deg C. For the 0Kh16N15M3B steel a continuous increase in the yield limit and a decrease in plasticity are observed at both test temperatures. The measurement of the amount of the ferrite component has shown that in the process of thermostating a α-γ transformation takes place in the deformed steel. Irradiation at 450-500 deg C leads to variation in mechanical properties and structures of steels. The value of variations dependens on the degree of deformation, the integral flux of irradiation and the chemical composition of steels. It has been established that the properties of deformed steels in the process of irradiation at 450-500 deg C up to the integral flux of 2.6x1021n/cm2 charge rather due to a thermal effect than to a radiation one. The 1Kh18N10T steel shows a greater tendency to swelling against the 0Kh16N15M3B steel. Cold deformation and thermomechanical treatment reduce the swelling of the 1Kh18N10T and 0Kh16N15M3B steels, in case the dislocation density in the steel structures is high