Brunčko Mihael, Kirbiš Peter, Anžel Ivan, Gusel Leo, Feizpour Darja, Irgolič Tomaž, Vuherer Tomaž
Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, 2000 Maribor, Slovenia.
Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana, Slovenia.
Materials (Basel). 2023 Feb 28;16(5):2003. doi: 10.3390/ma16052003.
The impact and fracture toughness of a nanostructured, kinetically activated bainitic steel was determined using Standard methods. Prior to testing, the steel was quenched in oil and aged naturally for a period of 10 days in order to obtain a fully bainitic microstructure with a retained austenite content below 1%, resulting in a high hardness of 62HRC. The high hardness originated from the very fine microstructure of bainitic ferrite plates formed at low temperatures. It was determined that the impact toughness of the steel in the fully aged condition improved remarkably, whereas the fracture toughness was in line with expectations based on the extrapolated data available in the literature. This suggests that a very fine microstructure is most beneficial to rapid loading conditions, whereas material flaws such as coarse nitrides and non-metallic inclusions are the major limitation for obtaining a high fracture toughness.
采用标准方法测定了一种纳米结构的、经动力学激活的贝氏体钢的冲击韧性和断裂韧性。在测试之前，将该钢在油中淬火并自然时效10天，以获得残余奥氏体含量低于1%的全贝氏体微观组织，从而得到62HRC的高硬度。高硬度源于在低温下形成的非常细小的贝氏体铁素体板条微观组织。结果表明，完全时效状态下该钢的冲击韧性显著提高，而断裂韧性与基于文献中推断数据的预期相符。这表明非常细小的微观组织对快速加载条件最为有利，而诸如粗大氮化物和非金属夹杂物等材料缺陷是获得高断裂韧性的主要限制因素。
