Deformation of Bi-PST Crystals of TiAl Produced by Diffusion Bonding

1998 ◽  
Vol 552 ◽  
Author(s):  
D. Imamura ◽  
H. Hoshikawa ◽  
K. Kishida ◽  
H. Inui ◽  
M. Yamaguchi
Keyword(s):  
Plastic Strain ◽  
Yield Stress ◽  
Diffusion Bonding ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Strong Influence ◽  
Tensile Axis ◽  
Lamellar Microstructure ◽  
Deformation Modes

ABSTRACTDiffusion bonded bi-PST crystals of three different series were prepared and they were deformed in tension at room temperature. Yield stress and elongation exhibited by bi-PST crystals consisting of component crystals with the lamellar microstructure aligned along the tensile axis do not significantly differ from those of component crystals. Plastic strain incompatibility at the interface exerts a strong influence on the deformation behavior of bi-PST crystals when the incompatibility activates additional deformation modes which are much harder than deformation modes operative in each component crystal.

scholarly journals The Deformation Behavior of Oxygen-Modified Ti-29Nb-13Ta-4.6Zr(wt.%)

2020 ◽  
Vol 321 ◽  
pp. 11003
Author(s):  
V. Khademi ◽  
H. Liu ◽  
M. Nakai ◽  
M. Niinomi ◽  
C.J. Boehlert
Keyword(s):  
Electron Microscope ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Tensile Axis ◽  
Deformation Mode ◽  
The Other ◽  
Work Hardening Rate ◽  
Elongation To Failure ◽  
Deformation Modes ◽  
Scanning Electron

A series of Ti-29Nb-13Ta-4.6Zr(wt.%) {TNTZ} alloys containing either 0.1, 0.3 or 0.7(wt.%) oxygen (O) were room-temperature tensile tested inside a scanning electron microscope to evaluate the effect of O on the deformation evolution. The deformation modes observed for TNTZ-0.1O, which exhibited the largest elongation-to-failure and lowest strength of all the alloys, were deformation-induced α”-martensitic transformation, {332}<113> twinning, and <111> slip. For the other two alloys, <111> slip was the dominant deformation mode, where TNTZ-0.7O exhibited more homogeneous and extensive slip, a higher frequency of cross slip, and a higher work-hardening rate, all of which contributed to both its strength and elongation-to-failure being greater than that for TNTZ-0.3O. TNTZ-0.3O exhibited the greatest tendency for cracking, which generally occurred on grain boundaries perpendicular to the tensile axis, leading to the lowest elongation-to-failure of all the alloys.

scholarly journals The Prospects for Mechanical Ratcheting of Bulk Metallic Glasses

2003 ◽  
Vol 806 ◽  
Author(s):  
Wendelin J. Wright ◽  
R. H. Dauskardt ◽  
W. D. Nix
Keyword(s):  
Plastic Strain ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Tensile Axis ◽  
Uniaxial Stress ◽  
Temperature Deformation ◽  
Steel Alloys ◽  
Cyclic Torsion ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

ABSTRACTThe major mechanical shortcoming of metallic glasses is their limited ductility at room temperature. Monolithic metallic glasses sustain only a few percent plastic strain when subjected to uniaxial compression and essentially no plastic strain under tension. Here we describe a room temperature deformation process that may have the potential to overcome the limited ductility of monolithic metallic glasses and achieve large plastic strains. By subjecting a metallic glass sample to cyclic torsion, the glass is brought to the yield surface; the superposition of a small uniaxial stress (much smaller than the yield stress) should then produce increments in plastic strain along the tensile axis. This accumulation of strain during cyclic loading, commonly known as ratcheting, has been extensively investigated in stainless and carbon steel alloys, but has not been previously studied in metallic glasses. We have successfully demonstrated the application of this ratcheting technique of cyclic torsion with superimposed tension for polycrystalline Ti–6Al–4V. Our stability analyses indicate that the plastic deformation of materials exhibiting elastic–perfectly plastic constitutive behavior such as metallic glasses should be stable under cyclic torsion, however, results obtained thus far are inconclusive.

Room-Temperature Deformation Behavior in the Localized Regions W-80vol%Cu Composite

2006 ◽  
Vol 15-17 ◽  
pp. 255-260
Author(s):  
H. Hanado ◽  
Yutaka Hiraoka
Keyword(s):  
Plastic Strain ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Testing Machine ◽  
Temperature Deformation ◽  
High Magnification ◽  
Bend Testing ◽  
Before And After ◽  
Point Bend ◽  
Heterogeneous Deformation

Room-temperature deformation behavior in the localized regions of W-80vol%Cu composite was investigated in this study. Plastic strain of about 10 % was added to the specimen at room temperature using a three-point bend testing machine. Then deformation behavior in a localized region was investigated using a high-magnification SEM photograph before and after deformation. Results are summarized as follow. (1) In a localized region near a large pore, heterogeneous deformation had occurred as expected. (2) In a region apart from a pore, mostly homogeneous deformation occurred but occasionally heterogeneous deformation occurred.

Deformation Behavior of Fe-Al Single Crystals Containing Fe2AlTi Precipitates

2018 ◽  
Vol 941 ◽  
pp. 1372-1377
Author(s):  
Hiroyuki Y. Yasuda ◽  
Hiroyuki Yakage ◽  
Yunima Shinohara ◽  
Ken Cho
Keyword(s):  
Single Crystals ◽  
Yield Stress ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Precipitation Hardening ◽  
High Strength ◽  
Misfit Strain ◽  
High Yield ◽  
High Yield Stress ◽  
Anti Phase Boundary

Fe-20Al-5Ti (at.%) single crystals composed of the bcc Fe-Al matrix and the Fe2AlTi precipitates with the L21 structure was examined. In the single crystals furnace-cooled (FC) from 1373 K to room temperature, coarse Fe2AlTi phase about 300 nm in diameter were precipitated in the bcc matrix. A misfit strain and a dissolution temperature of the L21 precipitates are +0.59% and 1151 K, respectively. The single crystals exhibited high yield stress above 600 MPa up to 973 K while further increase in temperature resulted in a decrease in yield stress due to the dissolution of the precipitates. In the FC crystals, 1/2<111> dislocations in the bcc matrix bypassed the coarse L21 precipitates due to their large misfit strain, resulting in high strength. In contrast, the fine L21 precipitates about 30 nm in diameter were observed in the crystals after solutionization and annealing at 873 K. The crystals with the fine L21 precipitates demonstrated high yield stress above 1100 MPa at and below 773 K. Uncoupled or paired 1/2<111> dislocations cut the fine L21 precipitates, leaving an anti-phase boundary (APB) inside the precipitates. The APB inside the precipitates was considered to be responsible for strong precipitation hardening.

Deformation Behavior of Fe-Al-Co-Ti Single Crystals Containing Co2AlTi Precipitates

2016 ◽  
Vol 879 ◽  
pp. 2210-2215 ◽  
Author(s):  
Hiroyuki Y. Yasuda ◽  
Ryota Kobayashi
Keyword(s):  
Single Crystals ◽  
Yield Stress ◽  
Deformation Behavior ◽  
Room Temperature ◽  
High Strength ◽  
Misfit Strain ◽  
High Yield ◽  
Precipitate Size ◽  
High Yield Stress

Deformation behavior of Fe-15Al-18Co-3Ti (at.%) single crystals containing the Co2AlTi precipitates was examined. In the single crystals furnace-cooled (FC) from 1373 K to room temperature, coarse Co2AlTi phase with the L21 structure was precipitated in the bcc matrix. The L21 phase showed a cuboidal shape with a misfit strain of 0.59%. It is also noted that large amount of Fe substituted for Co in the Co2AlTi precipitates. The FC single crystals exhibited high yield stress above 600 MPa up to 823 K while further increase in temperature resulted in a decrease in yield stress. In the FC crystals, 1/2<111> dislocations in the bcc matrix bypassed the coarse L21 precipitates due to their large misfit strain, resulting in high strength. In contrast, the fine L21 precipitates about 30 nm in diameter were observed in the crystals after solutionization and annealing at 823 K. The crystals with the fine L21 precipitates demonstrated high yield stress above 1400 MPa at room temperature. Paired 1/2<111> dislocations cut the fine L21 precipitates, which led to high strength. The dependence of the yield stress on the precipitate size was also discussed.

Plastic Deformation Behavior of Oriented Ni3V Crystals with D022 Structure

2006 ◽  
Vol 980 ◽  
Author(s):  
Koji Hagihara ◽  
Mayumi Mori ◽  
Yukichi Umakoshi
Keyword(s):  
Plastic Deformation ◽  
Single Crystals ◽  
Yield Stress ◽  
High Temperatures ◽  
Low Temperatures ◽  
Deformation Behavior ◽  
Plastic Deformation Behavior ◽  
Deformation Modes ◽  
Rapid Drop

AbstractPlastic deformation behavior of Ni3V with D022 structure was examined using the single crystals containing two dominant variants of three. Three deformation modes were confirmed to be operative depending on temperature and loading orientation. {111}1/6<112] twinning and/or {111}<110] slip is dominantly operative at low temperatures, but {111}1/2<112] slip is activated at high temperatures accompanied by a rapid drop of yield stress.

Plastic deformation of θ ' in Al-4%Cu alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 576-577
Author(s):  
Shrikant P. Bhat
Keyword(s):  
Deformation Behavior ◽  
Room Temperature ◽  
Electron Microscopic Observation ◽  
Bulk Alloy ◽  
Electron Microscopic ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Orowan Mechanism ◽  
The Subject ◽  
Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

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

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.

A Modified Peric Model for Al-Mg Alloy Sheet with Rate-Independent Initial Yield Stress at Warm Temperatures

2019 ◽  
Vol 287 ◽  
pp. 3-7
Author(s):  
Yong Zhang ◽  
Qing Zhang ◽  
Yuan Tao Sun ◽  
Xian Rong Qin
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Yield Stress ◽  
Constitutive Models ◽  
Mg Alloy ◽  
Initial Yield Stress ◽  
Initial Yield ◽  
Rate Dependent ◽  
Dependent Flow

The constitutive modeling of aluminum alloy under warm forming conditions generally considers the influence of temperature and strain rate. It has been shown by published flow stress curves of Al-Mg alloy that there is nearly no effect of strain rate on initial yield stress at various temperatures. However, most constitutive models ignored this phenomenon and may lead to inaccurate description. In order to capture the rate-independent initial yield stress, Peric model is modified via introducing plastic strain to multiply the strain rate, for eliminating the effect of strain rate when the plastic strain is zero. Other constitutive models including the Wagoner, modified Hockett–Sherby and Peric are also considered and compared. The results show that the modified Peric model could not only describe the temperature-and rate-dependent flow stress, but also capture the rate-independent initial yield stress, while the Wagoner, modified Hockett–Sherby and Peric model can only describe the temperature-and rate-dependent flow stress. Moreover, the modified Peric model could obtain proper static yield stress more naturally, and this property may have potential applications in rate-dependent simulations.

Sign in / Sign up

Export Citation Format

Share Document