Analysis of elastic-plastic deformation in TiAl polycrystals

A three-dimensional crystal plasticity model for duplex Ti–6Al–4V

“…In this sense, the model presented is novel in that it combines and expands on ideas developed in previous models for single phase hcp materials such as titanium, magnesium, and zinc (Kalidindi, 1998;Philippe et al, 1998;Staroselsky and Anand, 2003) as well ideas from the multiphase crystal plasticity literature on TiAl alloys (Barton and Dawson, 2001;Brockman, 2003;Grujicic and Batchu, 2001;Hasija et al, 2003;Morrissey et al, 2003;Schoenfeld and Kad, 2002). This paper is organized as follows: Section 2 will give a detailed overview of the relevant microstructural features and deformation mechanisms of Ti-64, followed by the presentation of the constitutive model in Section 3.…”

“…The lamellar a + b colonies are not explicitly modeled as alternating a and b laths as this would be computationally prohibitive due to the small thicknesses of the laths compared to the size of a microstructural statistical volume element of Ti-64. Instead, in an approach similar to that used by Brockman (2003) to model lamellar PST c-TiAl, both hcp and bcc slip systems are used in an equivalent grain-scale representation of a + b colonies. In this approach isostress is assumed in the lamellae and the colonies have 24 possible slip systems: three basal h1 1 2 0ið0 0 0 1Þ, three prismatic h1 1 2 0if1 0 1 0g, six hai first-order pyramidal h1 1 2 0if1 0 1 1g, and 12 h1 1 1if1 1 0g.…”

Numerical prediction of the stress–strain response of a lamellar γTiAl polycrystal using a two-scale modelling approach

“…Numerical methods have been developed for understanding the deformation and fracture behaviour on micro-and macro-scale using crystal plasticity or continuum damage models [10][11][12][13][14]. In particular, the crystal plasticity based constitutive modelling approaches serve as a valuable tool for characterising the anisotropic deformation of two-phase γTiAl alloys in different aspects, for example, combining the modelling of local stress-strain behaviour with nanoindentation testing across the lamellae to explore grain scale plasticity [15] or finding simplification limits of grain-wise homogenisation to predict overall plasticity [16].…”

Reviewing the class of Al-rich Ti-Al alloys: modeling high temperature plastic anisotropy and asymmetry

“…Anisotropy of Ti-rich side alloys is highly pronounced irrespective of whether it is at room temperature (Werwer and Cornec 2006) or at high temperature (Wegmann et al 2000). Room temperature plastic anisotropy of similar Ti-rich TiAl lamellar single crystals has also been discussed in Zambaldi et al (2011), Zambaldi and Raabe (2010), and among others, where they showed that the maximum yield stress occurs when lamellar direction is perpendicular to the compression axis i.e φ = 90°, stress is the minimum when approximately φ = 45°, and at φ = 0°stress is in between (Brockman 2003, Fujiwara et al 1990). The ratio of the highest to the lowest values of yield stress is almost 8:1.…”