Deformation behavior of CP-titanium under strain path changes: Experiment and crystal plasticity modeling. (January 2022)

• Record Type: Journal Article
• Authors: Wroński, M.; Kumar, M. Arul; McCabe, R.J.; Wierzbanowski, K.; Tomé, C.N.
• Is Part Of: International journal of plasticity. Volume 148(2022)
• Publication Date: 2022-01
• Subjects: Crystal plasticity -- Strain path changes -- Titanium -- Dislocation density -- Twinning -- De-twinning -- Double-twinning; Plasticity -- Periodicals; Plasticité -- Périodiques; Plasticity; Periodicals; 620.11233
• DOI: 10.1016/j.ijplas.2021.103129
• Languages: English
• ISSNs: 0749-6419

Abstract

Highlights: Effect of strain path changes on mechanical behavior and twinning microstructure development in commercially pure titanium is studied using experiments and a crystal plasticity model. Detailed EBSD based characterization of boundary misorientation angles distribution is developed to analyze the evolution of deformation twins. A model accounts for the back stress induced by dislocations and twins is developed to simulate twinning, detwinning and double twinning processes. Developed model correctly predicts the stress-strain response, texture and twinning microstructure evolution for sequential compression loadings along different directions. Abstract: The deformation behavior of commercially pure rolled titanium subjected to strain path changes is studied using experiments and a crystal plasticity model. Four different loading combinations are performed at room temperature to study the activation of slip, twinning, de-twinning and double-twinning in hexagonal closed packed titanium. The strain paths considered are: rolling direction compression (RDC) followed by normal direction compression (NDC), RDC followed by transverse direction compression (TDC), NDC followed by RDC, and NDC followed by TDC. An EBSD-based analysis of the distribution of boundary misorientation angles before and after reload was developed to analyze the evolution of { 10 1 ¯ 2 } tensile and { 11 2 ¯ 2 } compression twins. This analysis supports the model results concerning the treatment of twin reorientation. A de-twinning and double-twinning model accounting for back stress effects, an important feature of strain path changes, is implemented within the framework of the visco-plastic self-consistent (VPSC) model along with a dislocation density (DD) based hardening scheme. In the model, plasticity is accommodated by prismatic 〈a〉, basal 〈a〉 and pyramidal 〈 c + a 〉 slip modes, and { 10 1 ¯ 2 } tensile and { 11 2 ¯ 2 } compression twinning modes. The VPSC model predicts the evolution of twinning, de-twinning and double-twinning processes for both tensile and compression twinning modes under strain path change. The model predicts macroscopic stress-strain response, texture evolution, and twin volume fraction that are in agreement with experimental observations. The evolution of texture is investigated in detail by separately analyzing the twinned domains, rather than the evolution of the global texture.