【摘要】 利用X射线应力分析仪和在线加载装置测试了紧凑拉伸(compacttension,CT)Be试样缺口前端的应力分布,利用万能拉伸试验机、引伸计和扫描电镜研究了紧凑拉伸Be试样的断裂行为。研究表明:样品加工缺陷如缺口在载荷作用下形成应力集中,样品首先在此开裂,获得了紧凑拉伸铍试样的载荷-裂纹张开曲线和平面应变断裂韧性为15.4MPam。扫描电镜观察表明Be断口呈现解理特征,紧凑拉伸试样断口呈现出3个特征区。裂纹尖端扩展观察表明沿基滑移面形成解理微裂纹,这些微裂纹长大后受主应力控制。利用断裂韧性评估了Be材存在微裂纹时的断裂强度。更多还原

【Abstract】 The compact tension (CT) specimens of beryllium were employed to study the fracture behavior and mechanical properties. The local stress distribution near a notch in CT beryllium was measured by combination of an X-ray stress analysis and a custom-designed load device, and the fracture morphology was observed by SEM. The results show that the local stress near notch tip is much higher than that in other areas, and a cracking occurs firstly in this area. The loading-cracking displacement curve of the CT Be was obtained, and the fracture toughness value was calculated from the curve. The CT specimen fracture surfaces mainly exhibit a cleave morphology with three typical areas. Some open micro-cracks along the basal slip plane were formed in the crack tip, and its growth was controlled by primary stress after reaching a critical length. The tensile strength was evaluated by the fracture toughness theory when a crack existed in the Be material.更多还原