Substructures of deformation twins and twin intersections in a Ti–45Al–8Nb–2.5Mn alloy heavily deformed at room temperature

Zhang, L.C.; Chen, G.L.; Ye, H.Q.

doi:10.1016/s0921-5093(00)01379-4

Cited by 14 publications

(4 citation statements)

References 24 publications

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“…4 is nearly parallel to the trace of the ) 0 1 10 ( prismatic plane in the two twins, which can be referred to as PP interface. It should be noted that the atomic image close to the PP boundary is more blurred than those far away from the PP boundary, indicating a high lattice distortion caused by local high stress concentration, as reported by some previous researches [10,11,[22][23][24]. This is also consistent with the high residual dislocation content on the TTB as discussed previously [10,11].…”

Section: Accepted Manuscriptsupporting

confidence: 89%

Observations on the intersection between 101̅2 twin variants sharing the same zone axis in deformed magnesium alloy

Sun

Zhang

Ren

et al. 2015

Materials Characterization

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Section: Accepted Manuscriptsupporting

confidence: 89%

Observations on the intersection between 101̅2 twin variants sharing the same zone axis in deformed magnesium alloy

Sun

Zhang

Ren

et al. 2015

Materials Characterization

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“…10). Such twinned wedges have been observed in a variety of materials including austenitic steel, Co -Fe alloys [45], and TiAl [6,81].…”

Section: Multiple Twin Interactionmentioning

confidence: 99%

Between microscopic and mesoscopic descriptions of twin–twin interaction

Müllner¹

2006

MEKU

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On a microscopic scale, deformation twinning is carried by the motion of twinning disconnections. A disconnection is an interfacial line defect characterized by a Burgers vector, a line vector, and a step vector. The Burgers vector (dislocation component of the disconnection) carries the deformation while the step vector (ledge component) carries the transformation from one twin variant to the other. On a mesoscopic scale, the deformation produced by twinning is a simple shear. A moving disclination dipole provides a mesoscopic model accounting for the twinning shear. Twin -twin interaction processes including the intersection of twins, the formation of structured twins, and the nucleation of cracks, may feature very complex mechanisms when analyzed on a microscopic scale. It turns out, however, that these mechanisms are controlled by the properties of large disconnection groups containing up to 10 000 disconnections and more. These properties are sufficiently well approximated in the disclination dipole model. The disclination model for twin -twin interaction predicts orientation and volume fractions of secondary twins. The model also predicts the nucleation of cracks and crack growth. The disclination model was used to analyze the ductile-to-brittle transition of austenitic steel deformed at low temperature. The mesoscopic disclination model for twinning is successful because it accounts for the properties and mechanisms of disconnection groups.

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“…During the thermal cycles, the structural change of the twin boundaries was intrinsically related to the change of the internal stress configuration in the individual grains. Moreover, lattice and twinning dislocations could either interact with each other or move towards lamellar boundaries, or deformation twin boundaries, being then pinned by them [19]. These processes may lead to local stress concentrations and formation of various substructures that may play an important role in accelerating effectively the local stress concentration and promoting the formation of microcracks [20].…”

Section: Resultsmentioning

confidence: 99%

Effect of thermocycling on the microstructure of Ti-6Al-4V alloy in simulated low Earth orbit space environment

Yang

et al. 2016

Sci. China Mater.

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The study of material damage and its physical mechanisms, the deep understanding of material performance degradation processes, and the improvement of key materials and devices used in a space environment are undoubtedly of critical scientific importance. This work investigated the mechanical properties and microstructures of the Ti-6Al-4V alloy subjected to thermocycling in a simulated low Earth orbit (LEO) space environment by using microhardness tests, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results revealed an initial increase in hardness with the number of cycles, followed by a subsequent decrease. After 300 thermal cycles, many cavities were formed at the two-phase interface of the Ti-6Al-4V alloy. The dominating structures were transformed into dislocation cell substructures of larger size. After 500 cycles, the central structures in the sample were subgrains evolving by dislocation cells, as well as intragranular twins and jogs structures. The relationship between microstructural evolution and thermal fatigue in LEO space environment was discussed, which may help predict the fatigue damage of materials.

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Substructures of deformation twins and twin intersections in a Ti–45Al–8Nb–2.5Mn alloy heavily deformed at room temperature

Cited by 14 publications

References 24 publications

Observations on the intersection between 101̅2 twin variants sharing the same zone axis in deformed magnesium alloy

Observations on the intersection between 101̅2 twin variants sharing the same zone axis in deformed magnesium alloy

Between microscopic and mesoscopic descriptions of twin–twin interaction

Effect of thermocycling on the microstructure of Ti-6Al-4V alloy in simulated low Earth orbit space environment

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