Intrinsic coupling between twinning plasticity and transformation plasticity in metastable β Ti-alloys: A symmetry and pathway analysis. (1st September 2020)

• Record Type: Journal Article
• Authors: Gao, Yipeng; Zheng, Yufeng; Fraser, Hamish; Wang, Yunzhi
• Is Part Of: Acta materialia. Volume 196(2020)
• Page Start: 488
• Page End: 504
• Publication Date: 2020-09-01
• Subjects: Titanium alloys -- Plasticity -- Phase transformation -- Deformation twinning -- Crystal symmetry; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2020.07.020
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: In addition to conventional dislocation plasticity, mechanical twinning and structural phase transformations are another two important plasticity carriers. Although both are symmetry-breaking processes and theories to treat each of them individually have been well-established, the intrinsic coupling between the two has not been investigated. Here we employ a phase transition graph approach to analyze systematically deformation modes arising from the interplay between mechanical twinning and phase transformations. Using metastable β Ti-alloys as an example, we show that mechanical twinning and phase transformations are intrinsically coupled in the symmetry-breaking processes, which results in multiple interconnected transformation and non-transformation deformation pathways and characteristic twinning modes. This work not only reveals the physical origin of unique twinning modes (e.g., {332}, {5 8 11} and {3 9 10} twins) and extended core structures of twin boundaries (e.g., nested twins) observed in experiments, but also provides a new insight into the enhanced plasticity of metastable β Ti-alloys through coupled twinning and transformation pathway engineering. Graphical abstract: The changes of atomic structures during the mechanical deformation and structural phase transformation in β titanium alloys. B, H and O stand for BCC, HCP and orthorhombic structural states, respectively. Image, graphical abstract