Yan Zhu, Wang Chao, Duan Hua, Hao Junjie, Yuan Guo
The State Key Laboratory of Rolling and Automation (RAL), Northeastern University, Shenyang 110819, China.
Materials (Basel). 2024 Sep 21;17(18):4644. doi: 10.3390/ma17184644.
This study investigated the microstructure, mechanical properties, and nucleation mechanism of acicular ferrite (AF) present in hot-rolled Ti deoxidized steel. In our experiments, the impact toughness of Ti deoxidized steel is significantly increased to 144 J at -20 °C, while those Mn and Al deoxidized steels are only 9 J and 18 J, respectively. Interlocked AF is the primary microstructure of Ti deoxidized steel. The second-phase particles of the core-shell-type structure, in which TiO is the nucleus and TiO is the outermost shell, act as effective nucleating agents to stimulate AF nucleation. The low lattice disregistry between TiO and AF is the main factor contributing to the production of AF. It is also revealed that TiO and MnS fulfill the particular orientation relationship, contributing to the formation of an Mn-depleted zone (MDZ) adjacent to MnS, proposed to be one of the possible mechanisms for promoting AF nucleation.
本研究调查了热轧钛脱氧钢中针状铁素体（AF）的微观结构、力学性能和成核机制。在我们的实验中，钛脱氧钢在-20°C时的冲击韧性显著提高到144 J，而锰和铝脱氧钢的冲击韧性分别仅为9 J和18 J。相互交错的AF是钛脱氧钢的主要微观结构。具有核壳型结构的第二相粒子，其中TiO为核心，TiO为最外层壳，作为有效的形核剂刺激AF形核。TiO与AF之间的低晶格错配是导致AF产生的主要因素。研究还表明，TiO和MnS满足特定的取向关系，有助于在MnS附近形成贫锰区（MDZ），这被认为是促进AF形核的可能机制之一。
