Scholarlink

<p>To address the demand for high-strength, high-toughness steels for lightweight new energy vehicles (NEVs), this study innovatively employs trace rare earth Cerium (Ce) to synergistically regulate the microstructural evolution and plastic instability behavior of a medium-manganese automotive steel (Fe−4Mn-0.1C). Experimental steels were prepared via melting, hot-rolling, cold-rolling, and intercritical annealing. Advanced characterization techniques, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were utilized to elucidate the mechanism of Ce microalloying. The results demonstrate that Ce forms AlCeO<sub>3</sub>/MnS composite inclusions, which effectively pin grain boundaries, refining the prior austenite grain size by 29.55% and 25.38% while significantly enhancing size distribution homogeneity. Ce addition suppresses the formation of blocky ferrite during cold-rolling and reduces the size of carbonitrides by 23.47% and 19.66%, respectively, through interfacial energy optimization, concurrently improving the thermal stability of retained austenite. Critically, Ce markedly inhibits plastic instability phenomena. The non-Ce steel exhibited pronounced Lüders banding and Portevin–Le Chatelier (PLC) serrations. The addition of 10&#xa0;ppm Ce resulted in attenuated Lüders banding and reduced PLC serration intensity. Remarkably, plastic instability was completely eliminated at 30&#xa0;ppm Ce. Fracture behavior optimization exhibited a Ce-content dependence: 10&#xa0;ppm Ce promoted uniform dimple distribution, increased dimple depth, and reduced cleavage cracking. However, increasing Ce to 30&#xa0;ppm reduced the average dimple size by 15.32% and induced an embrittlement tendency. These findings reveal that Ce microalloying synergistically achieves grain refinement, suppression of plastic instability, and toughness enhancement. This provides crucial technological support for the application of medium-manganese steels in safety-critical structural components for NEVs.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Synergistic Regulation of Microstructural Evolution and Plastic Instability by Trace Ce in Automotive Steels for New Energy Vehicles

  • 期刊论文

  • 发表日期：

    2025年12月29日

查看全文
  • Zhiyuan Wan,
  • Ruifeng Dong,
  • Yang Yang,
  • Qingling Cui

摘要

To address the demand for high-strength, high-toughness steels for lightweight new energy vehicles (NEVs), this study innovatively employs trace rare earth Cerium (Ce) to synergistically regulate the microstructural evolution and plastic instability behavior of a medium-manganese automotive steel (Fe−4Mn-0.1C). Experimental steels were prepared via melting, hot-rolling, cold-rolling, and intercritical annealing. Advanced characterization techniques, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were utilized to elucidate the mechanism of Ce microalloying. The results demonstrate that Ce forms AlCeO3/MnS composite inclusions, which effectively pin grain boundaries, refining the prior austenite grain size by 29.55% and 25.38% while significantly enhancing size distribution homogeneity. Ce addition suppresses the formation of blocky ferrite during cold-rolling and reduces the size of carbonitrides by 23.47% and 19.66%, respectively, through interfacial energy optimization, concurrently improving the thermal stability of retained austenite. Critically, Ce markedly inhibits plastic instability phenomena. The non-Ce steel exhibited pronounced Lüders banding and Portevin–Le Chatelier (PLC) serrations. The addition of 10 ppm Ce resulted in attenuated Lüders banding and reduced PLC serration intensity. Remarkably, plastic instability was completely eliminated at 30 ppm Ce. Fracture behavior optimization exhibited a Ce-content dependence: 10 ppm Ce promoted uniform dimple distribution, increased dimple depth, and reduced cleavage cracking. However, increasing Ce to 30 ppm reduced the average dimple size by 15.32% and induced an embrittlement tendency. These findings reveal that Ce microalloying synergistically achieves grain refinement, suppression of plastic instability, and toughness enhancement. This provides crucial technological support for the application of medium-manganese steels in safety-critical structural components for NEVs.