scholarly journals Room-temperature deformation of single crystals of transition-metal disilicides (TMSi2) with the C11b (TM=Mo) and C40 (TM=V, Cr, Nb and Ta) structures investigated by micropillar compression

2021 ◽  
pp. 117468
Author(s):  
Kyosuke Kishida ◽  
Satoshi Nakatsuka ◽  
Hiroaki Nose ◽  
Haruyuki Inui
Keyword(s):  
Transition Metal ◽  
Single Crystals ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Micropillar Compression

scholarly journals Room temperature deformation of single crystals of Ti5Si3 with the hexagonal D88 structure investigated by micropillar compression tests

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyosuke Kishida ◽  
Takayoshi Fukuyama ◽  
Takuto Maruyama ◽  
Haruyuki Inui
Keyword(s):  
Fracture Toughness ◽  
Transition Metal ◽  
Single Crystals ◽  
Room Temperature ◽  
Specimen Size ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Axis Orientation ◽  
Plastic Deformation Behavior ◽  
Micropillar Compression

Abstract Micropillar compression tests of Ti5Si3 single crystals were conducted at room temperature as a function of loading axis orientation and specimen size in order to investigate their room temperature plastic deformation behavior. Plastic flow by the operation of three deformation modes, {1$${\overline{1}}$$ 1 ¯ 00}[0001], {2$${\overline{1}}$$ 1 ¯ $${\overline{1}}$$ 1 ¯ 2} < 2$${\overline{1}}$$ 1 ¯ $${\overline{1}}$$ 1 ¯ $${\overline{3}}$$ 3 ¯  > and {1$${\overline{1}}$$ 1 ¯ 01} < 2$${\overline{1}}$$ 1 ¯ $${\overline{1}}$$ 1 ¯ $${\overline{3}}$$ 3 ¯  > slip were observed in [2$${\overline{2}}$$ 2 ¯ 05]-, [0001]- and [4$${\overline{3}}$$ 3 ¯ $${\overline{1}}$$ 1 ¯ 0]-oriented micropillar specimens deformed at room temperature, respectively. The CRSS values were evaluated to be very high above 2.7 GPa and were confirmed to increase up to about 6 GPa with the decrease in the specimen size. The fracture toughness values are evaluated to be 0.45 MPa m1/2 (notch plane // (0001)) and 0.73 MPa m1/2 (notch plane //(1$${\overline{1}}$$ 1 ¯ 00)) based on the results of micro-cantilever bend tests of chevron-notched specimens. The fracture toughness values are considerably lower than those for D8l-Mo5SiB2 and D8l-Nb5Si3 evaluated by the same method, indicating the inherent brittleness of binary Ti5Si3 compared to the other transition-metal silicides of the TM5Si3 type (TM: transition-metal).

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

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.

Room Temperature Deformation in “Soft” Orientation Nial Single Crystals

1990 ◽  
Vol 213 ◽  
Author(s):  
R.D. Field ◽  
D.F. Lahrman ◽  
R. Darolia
Keyword(s):  
Shear Stress ◽  
Elevated Temperature ◽  
Single Crystals ◽  
Room Temperature ◽  
Dislocation Motion ◽  
Temperature Deformation ◽  
Slip Planes ◽  
Schmid Factor ◽  
Critical Resolved Shear Stress ◽  
Active Slip

ABSTRACTA detailed study of deformation of NiAl single crystals in two soft orientations, <110> and <111>, has been conducted. The Schmid factor favors {100} slip in the former and {110} slip in the latter. Detailed dislocation analysis, critical resolved shear stress measurements, and slip trace analysis have been performed to determine the nature of dislocation motion and interactions in this material. Particular attention is given to prismatic loops formed during deformation, since the shapes of these loops reveal the active slip planes. Similar loop morphologies observed in elevated temperature [001] oriented tensile specimens are also discussed.

Room temperature deformation of CoSi2 single crystals

1992 ◽  
Vol 152 (1-2) ◽  
pp. 153-159 ◽  
Author(s):  
K. Ito ◽  
H. Inui ◽  
T. Hirano ◽  
M. Yamaguchi
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Temperature Deformation

The Effects Of Environment On The Room Temperature Deformation Of B2-Structured Fe-43Al Single-Crystals

2000 ◽  
Vol 646 ◽  
Author(s):  
I. Baker ◽  
D. Wu ◽  
E. P. George
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Single Crystals ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Single Slip ◽  
Fracture Surfaces ◽  
Boron Doped

ABSTRACTThe effects of the environment on the room temperature mechanical behavior of Fe-43Al single crystals have been studied. In both single slip and duplex slip crystals, fracture strains greater than 40% were obtained in specimens tested in oxygen, whereas elongations of ∼10% and ∼20% were obtained in air and vacuum, respectively. By comparison, similar elongations were obtained in boron-doped single-slip-oriented single crystals in both air and vacuum, but more ductility was obtained in air at slow strain rate. Fractography showed that testing in different environments produced marked differences in the fracture surfaces. Alternate loading of tensile specimens in air and under vacuum was performed at slow strain rates and showed changes in the flow stress between the two environments. The results are discussed in terms of the effects of moisture-produced hydrogen on the flow and fracture of FeAl.

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

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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