Fan Kuanyuan, Liu Baoxi, Liu Tianlong, Yin Fuxing, Belyakov Andrey, Luo Zhichao
Research Institute for Energy Equipment Materials, Tianjin Key Laboratory of Materials Laminating Fabrication and Interfacial Controlling Technology, School of Materials Science and Engineering, Hebei University of Technology, Tianjin, 300132, China.
Institute of New Materials, Guangdong Academy of Science, Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application, Guangzhou, 510651, China.
Sci Rep. 2024 Sep 27;14(1):22345. doi: 10.1038/s41598-024-70576-3.
Synergistically improving the strength and toughness of metallic materials is a central focus in the field of physical metallurgy. Yet, there is a noticeable lack of research in strengthening and toughening large-size metal components, whereas those components are extensively used in the modern industry. In this work, a deformation-assisted tempering (DAT) process was proposed to create a novel microstructure in 1.4 tons low-alloyed plain steel. After DAT treatment, the steel contains low dislocation density but high density of low-angle subgrain boundaries and dispersed spherical nano carbides. Such microstructure enables a much better combination of tensile strength and fracture toughness compared to the small-size quench and temper steels. The significant improvement in low-temperature impact toughness is due to the occurrence of delamination and subsequent large plastic deformation at the notch tip. The DAT process can provides a new strategy for the development of large-size fail-safe steel with excellent strength and fracture resistance.
协同提高金属材料的强度和韧性是物理冶金领域的核心关注点。然而，在大型金属部件的强化增韧方面，明显缺乏相关研究，而这些部件在现代工业中广泛应用。在这项工作中，提出了一种形变辅助回火（DAT）工艺，以在1.4吨的低合金碳钢中创建一种新型微观结构。经过DAT处理后，该钢的位错密度低，但小角度亚晶界密度高且有弥散分布的球形纳米碳化物。与小尺寸调质钢相比，这种微观结构能使抗拉强度和断裂韧性得到更好的结合。低温冲击韧性的显著提高归因于缺口尖端处分层的出现以及随后的大塑性变形。DAT工艺可为开发具有优异强度和抗断裂性能的大型安全钢提供一种新策略。
