用正电子湮没技术研究Ⅰ型裂纹尖端附近的损伤区

Study on the Damage in the Vicinity of Model I Crack Tip with Positron Annihilation Technique

用正电子湮没技术研究LY12CZ铝合金材料裂纹尖端附近的损伤区，采用正电子湮没寿命谱的两态捕获模型，将正电子在缺陷中湮没的平均寿命τ作为损伤变量的参量，得到裂纹尖端附近区域损伤值D的分布，并发现从裂尖到离裂尖大约1／2板厚处范围内具有三维效应。

LY12CZ aluminium alloy was chosen to study on the damage in the vicinity model I crack tip with positron annihilation experiment. By using two - state - capture model of life spectrum and regarding the average life span t of positron annihilation as the variation of the damage parameter, we obtained the damage D near the crack tip. The results show that the damage in the vicinity of crack tip is in fairly good agreement with the plane strain.