Effect of Irradiation with Low-Energy He2+ Ions on Degradation of Structural, Strength and Heat-Conducting Properties of BeO Ceramics

Abstract

The paper is devoted to the study of radiation-induced damage kinetics in beryllium oxide ceramics under irradiation with low-energy helium ions with fluences of 1015–1018 ion/cm2. It was revealed that at irradiation fluences above 1017 ion/cm2, a decrease in radiation-induced damage formation and accumulation rate is observed, which indicates the saturation effect. At the same time, the main mechanisms of structural changes caused by irradiation at these fluences are amorphization processes and dislocation density increase, while at fluences of 1015–1016 ion/cm2, the main mechanisms of structural changes are due to the reorientation of crystallites and a change in texture, with a small contribution of crystal lattice distorting factors. It was discovered that the radiation-induced damage accumulation as well as an implanted helium concentration increase leads to the surface layer destruction, which is expressed in the ceramic surface hardness and wear resistance deterioration. It was determined that with irradiation fluences of 1015–1016 ion/cm2, the decrease in thermal conductivity is minimal and is within the measurement error, while an increase in the irradiation fluence above 1017 ion/cm2 leads to an increase in heat losses by more than 10%.