回火形变对亚温淬火中碳低合金钢组织和性能的影响

Effect of Tempering Deformation on the Microstructure and Properties of Medium-Carbon Low-Alloy Steel After Intercritical Quenching

摘要:

中碳低合金钢在低温下的冲击韧性差，使其应用受到一定的限制。为增强中碳低合金的韧性，通过回火形变工艺构筑超细纤维的仿生组织，实现材料的强韧化。结果表明：经过回火形变后的42CrMo钢组织中包含细长纤维晶粒、<101>//RD的强织构及纳米碳化物，这种“类竹子”的仿生组织可显著提高材料的屈服强度和抗拉强度，抗拉强度达1.4 GPa以上；由于仿生纤维组织裂纹分层与分叉的增韧作用，这种新型材料具有更低的韧脆转变温度，在-80 ℃条件下的冲击韧性高达107 J，综合力学性能显著高于调质处理的42CrMo钢。该研究对高性能金属材料的设计和制造，具有一定的指导意义。

Abstract:

The application of medium carbon low alloy steel is limited due to its poor impact toughness at low temperatures. In this paper， the microfiber biomimetic tissue is constructed by the tempering deformation process to achieve the toughening of the material. The results show that the microstructure of 42CrMo steel after tempering deformation contains slender fiber grains， strong <101>//RD texture， and nano carbides. This "bamboo-like" biomimetic structure significantly improves the yield and tensile strength of the materials， and the tensile strength reaches more than 1.4 GPa. Due to the toughening effect of the crack delamination and bifurcation of the biomimetic fiber structure， this new material has a lower ductile-brittle transition temperature， the impact toughness is as high as 107 J at -80 °C， whose mechanical properties are significantly higher than those of the quenched and tempered 42CrMo steel. This work has guiding significance for the design and fabrication of high-performance metal materials.