Nucleation Analysis of Variant Transformed from Austenite with Σ₃ Boundary in High-Strength Low-Alloy Steel

Bin-Bin Wu¹，Zhi-Quan Wang¹，Cheng-Jia Shang^1,2，Yi-Shuang Yu¹，Devesh Misra³

1. Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing2. State Key Laboratory of Metal Material for Marine Equipment and Application3. Laboratory for Excellence in Advanced Steel Research,Department of Metallurgical,Materials and Biomedical Engineering,University of Texas at El Paso

摘 要：We elucidate here the effects of annealing twins on phase transformation products based on electron back-scatter diffraction analysis and corresponding microstructure visualization and quantification methods.Martensite and bainite were obtained by rapid continuous cooling and isothermal processing at different temperatures,respectively,which were designed to study variants formed in austenite with Σ₃ boundary.The isothermal transformation near martensite start（M_s） temperature was most conducive in obtaining the highest content of twin-related V₁/V₂ variant pair.Based on the classical nucleation theory of martensite and bainite,respectively,the role of austenite Σ₃ boundary in martensite and bainite transformation is illustrated.

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