نوع مقاله : علمی و پژوهشی
عنوان مقاله English
نویسنده English
Strain hardening plays a critical role in controlling the tensile stability, uniform elongation, and formability of advanced steels. However, in ferrite-based multiphase steels, where deformation is governed by phase interaction, strain partitioning, and evolving internal stresses, the conventional Hollomon strain hardening exponent (n) often provides only a limited description of hardening behavior because of its sensitivity to the selected fitting interval and its inability to represent the full hardening evolution. In the present study, a new parameter, termed the strain hardening capability parameter (SHCP), is introduced to provide a more comprehensive and physically meaningful characterization of tensile strain hardening in heterogeneous ferrite-based steels. A series of microstructures with different combinations of ferrite, cementite, and martensite were produced through controlled thermomechanical processing and subsequent intercritical treatment. Their microstructural features were characterized and correlated with tensile response under uniaxial loading. The SHCP was defined on the basis of the normalized hardening response over the uniform plastic deformation regime, thereby integrating the overall hardening capability of the material rather than representing it through a single fitting-dependent exponent. The results demonstrate that SHCP is highly sensitive to microstructural constitution and effectively distinguishes steels with different hard-phase fractions and deformation responses. In contrast to the conventional n-value, SHCP provides a more robust measure of the ability of multiphase steels to sustain hardening prior to necking. The proposed parameter therefore offers a physically interpretable and microstructure-sensitive framework for evaluating strain hardening behavior and for comparing the tensile performance of ferrite-based multiphase steels.
کلیدواژهها English
