scholarly journals Microstructure and Texture Evolution in a Post-dynamic Recrystallized Titanium During Annealing, Monotonic and Cyclic Loading

2020 ◽  
Vol 52 (1) ◽  
pp. 394-412
Author(s):  
P.-C. Zhao ◽  
B. Chen ◽  
Z.-G. Zheng ◽  
B. Guan ◽  
X.-C. Zhang ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Grain Growth ◽  
Texture Evolution ◽  
Coincidence Site Lattice ◽  
Lattice Rotation ◽  
Dislocation Slip ◽  
Boundary State ◽  
Basal Pole ◽  
Dynamic Recrystallization Behavior ◽  
Cp Ti

Abstract The post-dynamic recrystallization behavior of ultrafine-grained (UFG: 0.44 μm) cp-Ti under annealing, room temperature (RT) monotonic and cyclic loading was investigated across a range of temperatures and deformation rates wherever appropriate. By characterizing the grain and boundary structures, it was confirmed that recrystallization and grain growth occurred due to annealing (≥ 600 °C) and R = − 1 fatigue at RT. There was a noticeable 30 deg aggregation in misorientation distribution, along with the increased grain size. However, the hypothetical correlation between 30 deg aggregation and Σ13a or the other characteristic coincidence site lattice boundaries was found to be weak. The fatigue-induced grain growth is particularly intriguing for two reasons. First, the large monotonic deformation with low strain rate cannot trigger grain growth. Second, fatigue sharpened the basal intensity around the ND and caused a weaker texture component close to TD (load axis along the LD, perpendicular to the TD–ND plane). By contrast, high-temperature annealing only strengthened the UFG processing induced basal pole but without affecting its location. Novel insights into this fatigue-induced texture evolution in UFG cp-Ti has been provided. The lattice rotation during fatigue can be attributed to the combined effect of activation of prismatic $$ \langle a\rangle $$ ⟨ a ⟩ slip parallel to LD, and basal $$ \langle a\rangle $$ ⟨ a ⟩ slip perpendicular to it. The theoretically calculated stress to activate dislocation slip by assuming a non-equilibrium grain boundary state lent support to the above assertion. Moreover, the TEM observation evidently showed the characteristics of dislocation cross-slip and multiple slip in the grain interior. Graphical Abstract

Role of deformation twin on texture evolution in cold-rolled commercial-purity Ti

2008 ◽  
Vol 23 (11) ◽  
pp. 2954-2966 ◽  
Author(s):  
Yong Zhong ◽  
Fuxing Yin ◽  
Kotobu Nagai
Keyword(s):  
Grain Size ◽  
Cold Rolling ◽  
Texture Evolution ◽  
Dislocation Slip ◽  
Commercial Purity ◽  
High Deformation ◽  
Prediction And Control ◽  
Initial Texture ◽  
Deformation Level ◽  
Cp Ti

Texture evolution of a commercial-purity titanium (CP-Ti) during cold rolling was studied by means of x-ray diffraction (XRD) and electron back-scattered diffraction (EBSD). Twinning was identified to significantly contribute to deformation up to reductions of about 50%. Based on initial texture of the material investigated and twinning modes available in hexagonal close-packed (HCP) structures, the measured texture evolution can be interpreted in terms of (i) compressive twinning ({11¯22}〈11¯2¯3〉) within the two dominant initial texture components B ({0001}〈10¯10〉±40°TD) and E ({0001}〈11¯20〉±40°TD) and (ii) followed by tensile twinning ({10¯12}〈10¯1¯1〉) in the then-favorably reoriented twinned part. Reduction of grain size at high deformation inhibits further twinning and results in a stable texture evolution driven exclusively by dislocation slip. During cold rolling, the crystals of the initial texture component B first rotate to orientation M ({01¯10}〈2¯1¯12〉) by compressive twinning (primary), and then orientation M rotates to orientation D ({0001}〈11¯20〉) by tensile twinning (secondary). Meanwhile, the crystals of the initial component E first rotate to the orientation M′ ({14¯53}〈6¯5¯13〉) by compressive twinning (primary), and then orientation M′ rotates to the orientation A ({0001}〈10¯10〉) by tensile twinning (secondary). At higher deformation level, twinning was significantly depressed by strongly refined grain size, which resulted in the elimination of the transient texture components caused by slip. These results are useful for the prediction and control of the texture in titanium.

scholarly journals Mean Field Analysis of Orientation Selective Grain Growth Driven By Interface-Energy Anisotropy

1994 ◽  
Vol 343 ◽  
Author(s):  
J. A. Floro ◽  
C. V. Thompson
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Growth ◽  
Texture Evolution ◽  
Mean Field ◽  
Orientation Distribution ◽  
Interface Energy ◽  
Abnormal Grain Growth ◽  
Field Analysis ◽  
Energy Anisotropy

ABSTRACTAbnormal grain growth is characterized by the lack of a steady state grain size distribution. In extreme cases the size distribution becomes transiently bimodal, with a few grains growing much larger than the average size. This is known as secondary grain growth. In polycrystalline thin films, the surface energy γs and film/substrate interfacial energy γi vary with grain orientation, providing an orientation-selective driving force that can lead to abnormal grain growth. We employ a mean field analysis that incorporates the effect of interface energy anisotropy to predict the evolution of the grain size/orientation distribution. While abnormal grain growth and texture evolution always result when interface energy anisotropy is present, whether secondary grain growth occurs will depend sensitively on the details of the orientation dependence of γi.

Texture and Ductility of Ni3Al Foils

2011 ◽  
Vol 306-307 ◽  
pp. 116-119
Author(s):  
Masahiko Demura ◽  
Ya Xu ◽  
Toshiyuki Hirano
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Memory Effect ◽  
Texture Evolution ◽  
High Mobility ◽  
Two Stage ◽  
Texture Memory ◽  
Highly Effective ◽  
Cold Rolled

This article presents the texture evolution and the ductility improvement of the cold-rolled foils of boron-free Ni3Al during the recrystallization and the subsequent grain growth. The cold-rolled foils had sharp {110} textures. After the recrystallization at 873K/0.5h, the texture was disintegrated with several texture components. Interestingly, most of them had a single rotation relationship. i.e. 40˚ around <111>. With the progress of the grain growth, however, the texture returned to the sharp, cold-rolled textures. This two-stage texture evolution, called as “Texture memory effect”, was explained assuming a high mobility of the grain boundary with the 40˚<111> rotation relationship. The texture returning was highly effective to improve the ductility of the foils.

Mechanisms of Grain Growth in Free-Standing Nanograined Gold Thin Films

2005 ◽  
Vol 907 ◽  
Author(s):  
J. A. Gregg ◽  
K Hattar ◽  
C H Lei ◽  
I M Robertson
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Structural Changes ◽  
Dislocation Slip ◽  
Free Standing ◽  
Transmission Electron ◽  
Enhanced Properties ◽  
Gold Thin Films ◽  
Annealing Experiments

AbstractRetention of the enhanced properties reported for nanograined metallic systems requires that the nanostructure be insensitive to temperature and deformation. In situ transmission electron microscopy annealing experiments were employed to investigate the structural changes associated with the formation of micron-sized grains in nanograined evaporated gold thin films. This abnormal grain growth occurs randomly throughout the film. Twinning but not dislocation slip occurs in the growing grains until the grain size is in the hundreds of nanometer range. The twins appear to hinder growth and for grain growth to continue the twins must either be annihilated or be able to grow with the grain concurrently.

Development of Growth Texture in Nanocrystalline Fe-Ni Alloys

2005 ◽  
Vol 495-497 ◽  
pp. 749-754 ◽  
Author(s):  
Chang Sik Ha ◽  
Yong Bum Park
Keyword(s):  
Energy Density ◽  
Grain Growth ◽  
Fibre Type ◽  
Texture Evolution ◽  
Orientation Dependence ◽  
Texture Development ◽  
Fibre Texture ◽  
Abnormal Growth ◽  
Ni Alloys ◽  
Texture Change

In electroformed pure Ni and Fe-Ni alloys with nanometer-sized crystallites, grain growth that takes place during annealing results in a common texture change. With regard to the macrotextures, the as-deposited textures were of fibre-type characterized by strong <100>//ND and weak <111>//ND components, and the texture development due to grain growth was defined by strong <111>//ND fibre texture with the minor <100>//ND components. It was clarified by means of the microtexture analysis that abnormal growth of the <111>//ND grains occurs in the early stages of grain growth. The possible effects of the abnormal grain growth on the texture evolution have been discussed in terms of the orientation dependence of energy density.

A Role of Low Energy Grain Boundaries in the Abnormal Grain Growth in Fe-3%Si Alloy

2011 ◽  
Vol 127 ◽  
pp. 89-94 ◽  
Author(s):  
Ye Chao Zhu ◽  
Jiong Hui Mao ◽  
Fa Tang Tan ◽  
Xue Liang Qiao
Keyword(s):  
Grain Boundaries ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Dominant Role ◽  
Coincidence Site Lattice ◽  
Diffraction Method ◽  
Abnormal Grain Growth ◽  
Low Energy ◽  
Backscatter Diffraction

Low energy grain boundaries were considered to be important in abnormal grain growth by theoretical deduction. The disorientation angles and coincidence site lattice grain boundaries distribution of more than 20 Goss grains and their neighboring matrix grains in primary recrystallized Fe-3%Si alloy were investigated using an electron backscatter diffraction method. It was found that the frequency of low energy grain boundaries of Goss grains which are more likely to abnormally grow are higher than their neighboring matrix grains, which indicated that low energy grain boundaries play a dominant role in the abnormal grain growth of Fe-3%Si alloy. The result meets well with the abnormal grain growth theory.

Texture Evolution in Cu Films and Lines

2007 ◽  
Vol 990 ◽  
Author(s):  
Chia-Jeng Chung ◽  
David Field ◽  
No-Jin Park ◽  
Christy Woo
Keyword(s):  
Grain Growth ◽  
Strain Energy ◽  
Texture Evolution ◽  
Growth Conditions ◽  
Geometric Constraints ◽  
In Situ Observation ◽  
Processing Conditions ◽  
Cu Films ◽  
Unique Character

ABSTRACTGrain growth in polycrystalline films is controlled by the energetics of the surface, interface and grain boundaries as well as strain energy. The unique character of damascene lines fabricated from electroplated Cu films introduces the additional considerations of bath chemistry and geometric constraints. The moderate stacking fault energy of Cu allows for the development of a substantial twin fraction for certain growth conditions. This paper discusses in-situ observation of grain growth in Cu films and lines under various processing conditions. It is shown that for thicker films and for structures constrained within damascene trenches the energetics of twin boundary formation play a large role in texture development of these structures.

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