SrTiO3 Single Crystals Achieve 8% Plastic Strain When Tested in Compression at Room Temperature

ABSTRACTFully reversed strain-controlled, tension-compression tests were performed at room temperature to study cyclic-deformation properties of Ni3Ge single crystals. The cyclic deformation is performed with the stress axis parallel to the [1 1.94 2.69] direction at a strain rate of 1.0 × 10-4 s-1 and at a total-strain amplitude between 5.0 × 10-4 and 1.5 × 10-3. Cyclic strain-hardening occurs to saturation over the range of the employed strain amplitudes. The cyclic-stress amplitude is higher in compression than in tension at a plastic-strain amplitude larger than 1 × 10-5 where screw dislocations are operative. This stress asymmetry becomes more prominent (i.e., the mean stress-amplitude becomes larger in magnitude) as the plastic-strain amplitude becomes larger. At a plastic-strain amplitude less than 1 × 10-5 where edge dislocations are operative, the stress amplitude is symmetric. A similar stress asymmetry is also observed for monotonic flow stress. The cyclic hardening is explained by considering an interaction between the screw dislocations.

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Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096989 ◽

1981 ◽

Vol 39 ◽

pp. 52-53

Author(s):

D. L. Rohr ◽

S. S. Hecker

Keyword(s):

Plastic Strain ◽

Cell Walls ◽

Room Temperature ◽

Mechanical Response ◽

Biaxial Tension ◽

Initial Deformation ◽

Uniaxial Deformation ◽

Biaxial Deformation ◽

Stress States ◽

Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

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Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110118 ◽

1978 ◽

Vol 36 (1) ◽

pp. 594-595

Author(s):

N.J. Long ◽

M.H. Loretto ◽

C.H. Lloyd

Keyword(s):

Flow Stress ◽

Single Crystals ◽

Room Temperature ◽

Thin Foil ◽

Age Hardening ◽

Dispersion Strengthening ◽

Accurate Picture ◽

The Matrix ◽

Very High ◽

Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

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Bright field and weak-beam images of dislocations gliding on (001) planes in F.C.C. metals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108908 ◽

1978 ◽

Vol 36 (1) ◽

pp. 352-353

Author(s):

H. P. Karnthaler ◽

A. Korner

Keyword(s):

Single Crystals ◽

Dislocation Structure ◽

Room Temperature ◽

Stage Ii ◽

Bright Field ◽

Weak Beam ◽

Standard Orientation

In f.c.c. metals slip is observed to occur generally on {111} planes. Glide dislocations on intersecting {111} planes can react with each other and form Lomer-Cottrell locks which lie along a <110> direction and are sessile since they are split on two {111} planes. Cottrell already pointed out that these dislocations could glide on {001} planes if they were not split. The first study of this phenomenon has been published recently. It is the purpose of this paper to report some interesting new details of the dislocations gliding on {001} planes in pure Ni, Cu, and Ag deformed at room temperature.Single crystals are grown with standard orientation and strained into stage II. The crystals are sliced parallel to the (001) planes. The dislocation structure is studied by TEM and the Burgers vectors ḇ and glide planes of the dislocations are determined unambiguously.In Fig.l primary P and secondary S dislocations react and form composite dislocations K.

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Effect of trytophan as dopant on potassium acid phthalate single crystals

10.31221/osf.io/cn28k ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Single Crystals ◽

Room Temperature ◽

Visible Region ◽

X Ray Diffraction ◽

X Ray ◽

Slow Evaporation Technique ◽

Absorption Studies ◽

Evaporation Technique ◽

Potassium Acid Phthalate ◽

Acid Phthalate

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.

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Room-temperature synthesis, growth mechanisms and opto-electronic properties of organic–inorganic halide perovskite CH3NH3PbX3 (X = I, Br, and Cl) single crystals

CrystEngComm ◽

10.1039/d0ce01690j ◽

2021 ◽

Author(s):

Maryam Bari ◽

Hua Wu ◽

Alexei A. Bokov ◽

Rana Faryad Ali ◽

Hamel N. Tailor ◽

...

Keyword(s):

Electronic Properties ◽

Single Crystals ◽

Room Temperature ◽

Solubility Curve ◽

Inverse Temperature ◽

Growth Mechanisms ◽

Temperature Synthesis ◽

Room Temperature Synthesis ◽

Halide Perovskite ◽

Temperature Crystallization

Growth of MAPbX3 (X = I, Br, and Cl) single crystals by room temperature crystallization (RTC) method, and the crystallization pathway illustrated by the solubility curve of MAPbCl3 in DMSO, compared with inverse temperature crystallization (ITC) method.

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Observation of large Rashba spin–orbit coupling at room temperature in compositionally engineered perovskite single crystals and application in high performance photodetectors

Materials Today ◽

10.1016/j.mattod.2021.01.027 ◽

2021 ◽

Author(s):

Abd. Rashid bin Mohd Yusoff ◽

Arup Mahata ◽

Maria Vasilopoulou ◽

Habib Ullah ◽

Bin Hu ◽

...

Keyword(s):

Single Crystals ◽

High Performance ◽

Room Temperature ◽

Orbit Coupling ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Rashba Spin

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Room-temperature deformation of single crystals of ZrB2 and TiB2 with the hexagonal AlB2 structure investigated by micropillar compression

Scientific Reports ◽

10.1038/s41598-021-93693-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhenghao Chen ◽

Bhaskar Paul ◽

Sanjib Majumdar ◽

Norihiko L. Okamoto ◽

Kyosuke Kishida ◽

...

Keyword(s):

Single Crystals ◽

Plastic Flow ◽

Room Temperature ◽

Resolve Shear Stress ◽

Temperature Deformation ◽

Slip Systems ◽

Compression Tests ◽

Plastic Deformation Behavior ◽

Bulk Single Crystals ◽

Micropillar Compression

AbstractThe plastic deformation behavior of single crystals of two transition-metal diborides, ZrB2 and TiB2 with the AlB2 structure has been investigated at room temperature as a function of crystal orientation and specimen size by micropillar compression tests. Although plastic flow is not observed at all for their bulk single crystals at room temperature, plastic flow is successfully observed at room temperature by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> in ZrB2 and by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> in TiB2. Critical resolve shear stress values at room temperature are very high, exceeding 1 GPa for all observed slip systems; 3.01 GPa for {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> slip in ZrB2 and 1.72 GPa and 5.17 GPa, respectively for {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> slip in TiB2. The identified operative slip systems and their CRSS values are discussed in comparison with those identified in the corresponding bulk single crystals at high temperatures and those inferred from micro-hardness anisotropy in the early studies.

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