C300焊缝金属3种状态的组织和性能

Microstructures and properties of C300 weld metal under three states

采用光学显微镜、扫描电镜及透射电镜等分析了C300焊缝金属焊态、焊后固溶态及焊后固溶时效态的微观组织变化、强韧性特征及断口裂纹扩展路径。结果表明,经过时效处理,在马氏体基体上析出了金属间化合物强化相,同时伴随着软相逆转变奥氏体的产生。时效态焊缝的强、硬度提高,塑、韧性降低,断口的韧窝尺寸和裂纹扩展路径相对较小,裂纹扩展阻力较低。

Optical microscopy（OM）,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）were used to study the microstructures,strengths,toughness as well as propagation paths of cracks of C300 weld metal under weld state,solid solution state after welding and solid solution and aging state after welding.The results show that after aging treatment,intermetallic compound as a strengthening phase and reverted austenite as a softening phase form on martensitic matrix.The strength and hardness of weld metal under aging state increase,the plasticity and toughness decrease,the size of dimple and propagation path of crack are smaller and resistance of crack propagation is lower.