STUDY OF THE EFFECT OF EQUAL-CHANNEL ANGULAR PRESSING ON THE CLOSURE OF CASTING DEFECTS IN ZIRCONIUM ALLOYS

In this study, the effectiveness of the Equal Channel Angular Pressing (ECAP) method for closure of casting defects in the zirconium alloy Zr - 1 % Nb, widely used in nuclear power engineering, was studied. A FEM simulation of ECAP processing of a workpiece with an artificially created through defect with a diameter of 5 mm in matrices from different angles of the junction of the die channels was carried out (45°, 90°, 135°). The simulation was verified on a 135° die. The results showed that after two passes, the defect was practically eliminated, the remaining residual crack had a width of only 10 - 25 mm, which indicates the high efficiency of the method. Microstructural analysis revealed a significant grinding of grains to sizes 1 - 8 mm and an increase in the hardness of the material from 145 HV to 171.5 HV. The data obtained confirm the potential of the ECAP method for improving the microstructure and mechanical properties of zirconium alloy ingots.