Surface Microstructure of High Temperature Beryllium Implanted with Deuterium

Abstract

ABSTRACTWe have investigated implantation temperature effects on the formation of blisters on the surface of Be foils implanted with low energy, 1.5 keV, deuterium ions to doses ranging from 3×1016 to 1.2×1018 ions cm-2, a dose exceeding by far the saturation (≈1.8×1017 ions cm-2: 30% at.). The implantation temperature was varied from 293 K (RT) to 983 K. The samples have been characterized by scanning electron microscopy (SEM). For saturated samples, blisters were present even at high temperatures, viz 983 K, and no blisters were found for samples implanted below 20% at.. However, on samples in which a dramatic grain growth has been observed, blisters were found to decorate the grain boundaries and to interconnect with each other. The average blister diameter increases with increasing temperature, thus indicating the thermodynamical aspect of blister formation and coalescence. On the other hand, for low temperature (473 K), the surface structure that has developed is similar to that at RT, except for an increased most probable blister diameter and blister density, and there was no indication that the blisters ruptured. The blister skin thickness agrees well with the projected range of the implanted ions. Over-saturated samples at RT retained only ≈30% at., corroborating the observations that some blisters formed on already ruptured ones.