Incipient slip and long range plastic strain localization in microtextured Ti-6Al-4V titanium

Abstract

High resolution scanning electron microscope digital image correlation (SEM DIC) was performed in situ during uniaxial loading on Ti-6Al-4V rolled sheet titanium to determine the dependence of strain localization on microstructure and microtexture. Individual grains with preferred orientation for basal slip exhibited plastic localization along basal planes before macroscopic yielding. With additional strain, but still below macroscopic yielding, pyramidal and prismatic plastic activity was observed as slip bands transmitting across many grains and entire microtextured regions (MTRs). The localization of long range plastic strain occurred within MTRs that allowed for slip transmission across grains with low angle boundaries. The rolled sheet titanium material having strong [0001] and [1010] texture components showed pyramidal and prismatic type slip extending across entire MTRs at strains well below macroscopic yielding. These strain localization processes occur much earlier in straining and over lengthscales much longer than observed with conventional slip offset imaging. The implications for properties are discussed.

A dataset for the development, verification, and validation of microstructure-sensitive process models for near-alpha titanium alloys

“…For example, Bridier et al [6] have demonstrated slip transmission between primary-alpha and secondary-alpha colonies. Recently, Echlin et al [7] have highlighted the development of multi-alpha-particle slip bands traversing entire MTRs. Hence, it is important to have models available to simulate microstructure evolution at each length scale.…”

Composite structure of α phase in metastable β Ti alloys induced by lattice strain during β to α phase transformation

“…However, large amount of Moiré fringes were observed in the major α plate, as shown in Fig. 5 (a), indicating the shear of a 21 of the major α plate may be absorbed mainly by its prismatic slip [41,42], as it is well known that the prismatic slip of the α phase of the Ti has very small critical resolved shear stress (CRSS) [43,44]. Obviously the interface α particles further serve as sympathetic nuclei for the formation of the neighboring major α plate with the same orientation and eventually contribute to formation of the triangular variant cluster of three 60°/<11 0> α inter-2 related major α plates, as shown in Fig.…”

A Hierarchical Multiscale Modeling Investigation on the Behavior of Microtextured Regions in Ti-6242 α/β Processing

“…In Figure 2b, the compression direction is 45 • to the rolling direction (RD) and ND and will be referred to as the 45 • compression case later. RD, ND, and TD (transverse direction) were determined such that the ND pole figures coincided with the experimental measurement [17,18]. Note that both the compression direction and MTR orientation were changed in the mesoscale simulations, such that the uniaxial compression boundary condition can be conveniently applied, and the angle between the MTR axis and compression axis is the same as in the high temperature compression experiment [13,15].…”

“…A statistically equivalent representative volume element (RVE) was generated as the microscale model for hierarchical multiscale modeling. The initial orientation distribution and α p particle size distribution were prescribed from typically observed texture components in Ti-6242 [15,17,18]. An equivalent orientation distribution function (ODF) was calculated based on the EBSD (electron backscatter diffraction) measurement using the open source software MTEX [19].…”

“…In the 209 mm radius billet material, the extrusion fiber texture is not obvious, while MTRs have already formed [15]. Two typical MTR orientations were extracted based on experimental observations [17,18], which also exist in the pole figures of the 209 mm radius billet material [15]. Then, high-temperature compression experiments were performed on specimens from this billet material, against which we compared our hierarchical multiscale model.…”