Observing Dislocation Motion Induced By Laser Shock Peening In Ki

Laser shock peening (LSP) is applied to potassium iodide (KI) crystals. A selective etching technique is used to reveal the dislocation structure induced by the LSP process, confirming that LSP multiplies and moves dislocations in an alkali halide. Increasing the crystal temperature during LSP is shown to eliminate cracking along cleavage-planes caused by the LSP process and increases the range of dislocation motion in the crystal. LSP has long been used to increase surface toughness and fatigue life in metals. Having shown that LSP affects the mechanical properties in the ionic crystal KI, we propose studying the possible benefit of LSP in other halide crystals, including scintillators. One potential application might be reducing crack initiation and propagation at surfaces during Bridgman growth.