热处理对铀铌合金变形局域化的影响

Effects of Heat Treatment on Microstructure and Dynamic Shear Localization

摘要:

对多温度点人工时效(200 ℃/2 h、400 ℃/2 h、600 ℃/2 h)铀铌合金在冲击载荷作用下的绝热剪切带形成机理进行了研究，采用Hopkinson压杆装置对铀铌合金帽形样品进行了冲击加载，利用光学显微镜和扫描电镜对冲击后的回收样品进行了显微组织观察。结果表明，显微组织对剪切带的形成具有重要影响，只在200 ℃/2 h与600 ℃/2 h帽形样品台阶处观察到不同类型的绝热剪切带，400 ℃/2 h样品在冲击过程表现出韧性断裂与脆性断裂的特征，某些区域已经接近或达到熔点

Abstract:

Dynamic deformation and failure behavior of U-Nb alloy with different heat treatment (200 oC/2 h, 400 oC /2 h, 600 oC /2 h) were studied. Hat-shape specimens were used in an attempt to induce strain localization in U-Nb alloy. Dynamic load was applied to specimens by use of a Split Hopkinson Press Bar (SHPB) apparatus. The microstructure was examined by optical microscopy and scanning electron microscopy. Results show that the appearance of adiabatic shear bands (ASBs) is relative to the microstructure of material. Different kinds of ASBs are found in 200 oC/2 h and 600 oC/2 h specimens, while specimens (400 oC/2 h) exhibit dimple-like feature, indicating that significant melting takes place during deformation under high strain rate loading condition