Effect of Vanadium on Plastic Deformation in Llo TiAl Compound Alloys

1988 ◽  
Vol 133 ◽  
Author(s):  
Sung H. Whang ◽  
Yoo-Dong Hahn
Keyword(s):  
Plastic Deformation ◽  
Yield Stress ◽  
Uniaxial Compression ◽  
Fracture Stress ◽  
Room Temperature ◽  
Stacking Faults ◽  
Aluminum Concentration ◽  
Stress And Strain ◽  
Thin Foils ◽  
Miniature Specimens

ABSTRACTTernary Ti-Al-V (Llo) alloys containing vanadium up to 10 at.% and aluminum in the range of 50–55 at.% were prepared. Miniature specimens machined from these alloys were deformed in uniaxial compression at room temperature.The yield stress, and fracture stress and strain were determined with respect to vanadium and aluminum concentration. The deformed alloys were electropolished into thin foils and studied by TEM. In particular, the types of dislocations, stacking faults and twins in the Ti-Al-V alloys were investigated by TEM.

Deformation and its Structure in Llo Ti-Al-Nb Compound Alloys

1988 ◽  
Vol 133 ◽  
Author(s):  
Yoo-Dong Hahn ◽  
Sung H. Whang
Keyword(s):  
Temperature Dependence ◽  
Yield Stress ◽  
Uniaxial Compression ◽  
High Temperatures ◽  
Room Temperature ◽  
Fracture Strain ◽  
Positive Temperature ◽  
Deformation Structures ◽  
Miniature Specimens ◽  
Deformation Tests

ABSTRACTThe ternary TiAl-Nb (Llo) alloys stabilized at 1000°C for a week were prepared into miniature specimens for compressive deformation tests. The specimens were deformed in uniaxial compression at room temperature as well as various high temperatures. The yield stress and fracture strain were determined with respect to Nb concentration, and as a function of temperature to investigate positive temperature dependence.Dislocation structures and other deformation structures of the deformed alloys were studied by TEM.

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

scholarly journals Low-temperature degradation resistance and plastic deformation of ATZ ceramics stabilized by CaO

2021 ◽  
Vol 2103 (1) ◽  
pp. 012075
Author(s):  
AA Dmitrievskiy ◽  
DG Zhigacheva ◽  
VM Vasyukov ◽  
PN Ovchinnikov
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Plastic Deformation ◽  
Compressive Strength ◽  
Phase Composition ◽  
Low Temperature ◽  
Uniaxial Compression ◽  
Calcium Oxide ◽  
Tetragonal Phase ◽  
Room Temperature

Abstract In this work, the phase composition (relative fractions of monoclinic m-ZrO2, tetragonal t-ZrO2, and cubic c-ZrO2 phases) and mechanical properties (hardness, fracture toughness, compressive strength) of alumina toughened zirconia (ATZ) ceramics, with an addition of silica were investigated. Calcium oxide was used as a stabilizer for the zirconia tetragonal phase. It was shown that CaO-ATZ+SiO2 ceramics demonstrate increased resistance to low-temperature degradation. The plasticity signs at room temperature were found due to the SiO2 addition to CaO-ATZ ceramics. A yield plateau appears in the uniaxial compression diagram at 5 mol. % SiO2 concentration. It is hypothesized that discovered plasticity is due to the increased t→m transformability.

Atomic simulation of mechanical properties of irradiated iron

2019 ◽  
Vol 31 (02) ◽  
pp. 2050027
Author(s):  
Lei Ma ◽  
Changsheng Li ◽  
Ailong Zhang ◽  
Wangyu Hu
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Test ◽  
Room Temperature ◽  
Stacking Faults ◽  
Dynamics Simulation ◽  
Stress And Strain ◽  
Micro Structure ◽  
Atomic Simulation

The mechanical properties of irradiated iron are studied by molecular dynamics simulation. The initial models are irradiated with the energy of primary knocked-on atoms (PKA) of 10[Formula: see text]keV at 100, 300, 500 and 600 K, and then all the irradiated models are subjected to tensile test. The results reveal that the mechanical properties of irradiated iron are changed compared with un-irradiated iron, the yield stress and strain decrease after irradiation, and the irradiation causes the hardening of micro-structure at low temperature and high temperature, but it results in the softening of structure at room temperature. The plastic reduces for irradiated iron under tensile test, more stacking faults are formed in the crystal structure as the temperature increases.

Effect of void size and Mg contents on plastic deformation behaviors of Al-Mg alloy with pre-existing void: Molecular dynamics study

2022 ◽  
Author(s):  
Ning Wei ◽  
Ai-Qiang Shi ◽  
Zhi-Hui Li ◽  
Bing-Xian Ou ◽  
Si-Han Zhao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Yield Stress ◽  
Stacking Faults ◽  
Mg Alloy ◽  
Void Size ◽  
Plastic Mechanism ◽  
Deformation Properties ◽  
Eam Potential ◽  
Mg Content

Abstract The plastic deformation properties of cylindrical pre-void Aluminum-Magnesium (Al-Mg) alloy under uniaxial tension are explored using molecular dynamics simulations with embedded atom method (EAM) potential. The factors of Mg content, void size, and temperature are considered. The results show that the void fraction decreases with increasing Mg in the plastic deformation, and it is almost independent of Mg content when Mg is beyond 5%. Both Mg contents and stacking faults around the void affect the void growth. These phenomena are explained by the dislocation density of the sample and stacking faults distribution around the void. The variation trends of yield stress caused by void size are in good agreement with Lubarda model. Moreover, temperature effects are explored, the yield stress and Young's modulus obviously decrease with temperature. Our results may enrich and facilitate the understanding of the plastic mechanism of Al-Mg with defects or other alloys.

scholarly journals Brittle Fracture of Ice at 77 K

1975 ◽  
Vol 14 (71) ◽  
pp. 305-315 ◽  
Author(s):  
V. R. Parameswaran ◽  
Stephen J. Jones
Keyword(s):  
Brittle Fracture ◽  
Single Crystals ◽  
Uniaxial Compression ◽  
Fracture Stress ◽  
Room Temperature ◽  
Theoretical Strength ◽  
Strain Rates ◽  
Stress Strain

AbstractLaboratory-grown single crystals, both pure and HF-doped, and pure polycrystals of ice, as well as natural, columnar-grained ice from the River St Lawrence, have been deformed in uniaxial compression at 77 K at strain-rates between 10-5 and 10-3 s-1. Brittle fracture was observed, with stress-strain curves similar to those found for rocks at room temperature. The first cracks appeared at low stresses, ≈0.3 MN m-2, in agreement with theory, but the failure or fracture stress was high ≈50 MN m-2. The ratio of experimental to theoretical strength was o.28. HF doping of the single crystals had no effect at this temperature.

Plastic Deformations in Single Crystals of FePd with the L10 Structure

2008 ◽  
Vol 1128 ◽  
Author(s):  
Katsushi Tanaka ◽  
Wang Chen ◽  
Kyosuke Kishida ◽  
Norihiko L. Okamoto ◽  
Haruyuki Inui
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Yield Stress ◽  
Room Temperature ◽  
Positive Temperature ◽  
Plastic Deformations ◽  
L10 Structure ◽  
Critical Resolved Shear Stress

AbstractCompressive deformations of L10-ordered single crystals of FePd have been investigated from room temperature to 873 K. The critical resolved shear stress for superlattice dislocations is hard to determine resulting from buckling that occurs after a small amount of conventional plastic deformation. The CRSS for superlattice dislocations determined from yield stress is significantly larger than that of ordinary dislocations. The CRSS for octahedral glide of ordinary and superlattice dislocations are virtually independent of the temperature, and the positive temperature dependence of the yield stress is not observed for both, ordinary and superlattice dislocations, by the present experiments.

A Soft Ceramic Ti3SiC2 with Microscale Plasticity at Room Temperature

2007 ◽  
Vol 280-283 ◽  
pp. 1343-1346 ◽  
Author(s):  
Shi Bo Li ◽  
Hong Xiang Zhai
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Acid Solution ◽  
Basal Plane ◽  
Room Temperature ◽  
Damage Tolerance ◽  
Stacking Faults ◽  
Kink Band ◽  
Band Formation ◽  
Energy Absorbing

Microscale plasticity of Ti3SiC2 was investigated by Vickers hardness indentation. The surface layer of the hardness indentations was removed by acid solution to observe microstructure beneath the indentations, where a large number of bending, delamination and kinking grains were found. These features suggest that Ti3SiC2 is able to consume microdamage around the indentations. Numerous basal plane dislocations and stacking faults lying in Ti3SiC2 grains or accumulating at grain boundaries were observed. The basal plane dislocations play an important role in the microscale plastic deformation. The plasticity and damage tolerance for Ti3SiC2 at room temperature should be attributed to multiple energy absorbing mechanisms: grains bending, delamination, kink-band formation, and the basal plane slip, etc.

Measurement of the Dependence of Stress and Strain on Crystallographic Orientation in Cu and Al thin Films

1994 ◽  
Vol 356 ◽  
Author(s):  
E. M. Zielinski ◽  
R. P. Vinci ◽  
J. C. Bravman
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Yield Stress ◽  
Grain Growth ◽  
Crystallographic Orientation ◽  
Room Temperature ◽  
Abnormal Grain Growth ◽  
Stress And Strain ◽  
Al Thin Film ◽  
Individual Grains

AbstractThe orientational dependence of stress and strain was measured for (111) and (110) oriented grains in an Al thin film which hillocked upon heating, and (111) and (100) oriented grains in Cu thin films, one of which exhibits abnormal (100) grain growth. Results from the Al thin film were inconclusive in the evaluation of the Sanchez model for hillocking, however they indicate that the Nix model for the orientational dependence of yield stress is not applicable to individual grains at room temperature. Results from the Cu thin films suggest that suppression of (100) abnormal grain growth is due to isostress averaging among the grains of varying orientation.

scholarly journals Plastic deformation of gallium arsenide micropillars under uniaxial compression at room temperature

2007 ◽  
Vol 90 (4) ◽  
pp. 043123 ◽  
Author(s):  
Johann Michler ◽  
Kilian Wasmer ◽  
Stephan Meier ◽  
Fredrik Östlund ◽  
Klaus Leifer
Keyword(s):  
Plastic Deformation ◽  
Gallium Arsenide ◽  
Uniaxial Compression ◽  
Room Temperature
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