A dislocation-based constitutive model for the cyclic response of nanolath strengthened steels. (May 2019)

• Record Type: Journal Article
• Authors: Wang, Cheng; Xuan, Fu-Zhen; Zhao, Peng
• Is Part Of: International journal of mechanical sciences. Volume 155(2019)
• Page Start: 475
• Page End: 487
• Publication Date: 2019-05
• Subjects: Constitutive model -- Heterogeneous coarsening -- Cyclic softening -- Nanolath strengthened steel; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2019.03.010
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: Heterogeneous coarsening of nanolath structure is characterized under the low plastic strain level condition. Two regions in CSS curve are classified based on the cyclic softening behavior and the homogeneity of microstructural coarsening. A dislocation-based viscoplastic constitutive model is developed by introducing an intergranular back-stress related to the heterogeneous coarsening. The macroscopic mechanical behaviors and microstructural evolution of a nanolath strengthened steel at high/low plastic strain levels are reasonably reproduced. Abstract: Cyclic softening behavior at elevated temperature of nanolath strengthened steel was rationalized under different strain amplitudes. Results indicated that the evolution of internal stress components and the coarsening of subgrains are significantly depending on the plastic strain level. This paper proposes a dislocation-based viscoplastic constitutive model to represent the cyclic deformation response especially at low plastic strain level. The heterogeneous coarsening of subgrains is explicitly formulated via employing different evolution laws for multiple dislocation populations. An additional back-stress hardening component is introduced to account for the retarded cyclic softening. The cyclic deformation response and microstructural evolution of a nanolath strengthened steel at high/low plastic strain levels are perfectly reproduced. Graphical abstract: Image, graphical abstract