Deformation mechanisms in MoSi2at temperatures above the brittle-to-ductile transition temperature

1997 ◽  
Vol 75 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Daniel J. Evans ◽  
Frank J. Scheltens ◽  
John B. Woodhouse ◽  
Hamish L. Fraser
Keyword(s):  
Transition Temperature ◽  
Deformation Mechanisms ◽  
Brittle To Ductile Transition

Low temperature deformation mechanisms of icosahedral AlPdMn quasicrystals.

2003 ◽  
Vol 805 ◽  
Author(s):  
Michael Texier ◽  
Joël Bonneville ◽  
Anne Proult ◽  
Jacques Rabier ◽  
Ludovic Thilly
Keyword(s):  
Shear Stress ◽  
Transition Temperature ◽  
Low Temperature ◽  
Confining Pressure ◽  
Deformation Mechanisms ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Uniaxial Deformation ◽  
Brittle To Ductile Transition ◽  
Deformation Tests

ABSTRACTConfining pressure techniques, that superimpose a shear stress on an isostatic component, allowed us to plastically deform AlPdMn specimens at temperatures below the brittle-to-ductile transition temperature obtained using conventional uniaxial deformation tests at usual strain-rates. Microstructural observations associated with these low deformation temperatures are reported. They provide new insights on the elementary deformation mechanisms that control plasticity in this non-periodic structure.

Predicting the Brittle-to-Ductile Transition Temperatures for Surface Cracks in Pipeline Girth Welds: It’s Better Than You Thought

2008 ◽  
Author(s):  
Gery Wilkowski ◽  
David Rudland ◽  
Do-Jun Shim ◽  
David Horsley
Keyword(s):  
Transition Temperature ◽  
Surface Crack ◽  
Master Curve ◽  
Crack Depth ◽  
Temperature Shift ◽  
Transition Temperatures ◽  
Surface Cracks ◽  
Line Pipe ◽  
Brittle To Ductile Transition ◽  
Girth Welds

A methodology to predict the brittle-to-ductile transition temperature for sharp or blunt surface-breaking defects in base metals was developed and presented at IPC 2006. The method involved applying a series of transition temperature shifts due to loading rate, thickness, and constraint differences between bending versus tension loading, as well as a function of surface-crack depth. The result was a master curve of transition temperatures that could predict dynamic or static transition temperatures of through-wall cracks or surface cracks in pipes. The surface-crack brittle-to-ductile transition temperature could be predicted from either Charpy or CTOD bend-bar specimen transition temperature information. The surface crack in the pipe has much lower crack-tip constraint, and therefore a much lower brittle-to-ductile transition temperature than either the Charpy or CTOD bend-bar specimen transition temperature. This paper extends the prior work by presenting past and recent data on cracks in line-pipe girth welds. The data developed for one X100 weld metal shows that the same base-metal master curve for transition temperatures works well for line-pipe girth welds. The experimental results show that the transition temperature shift for the surface-crack constraint condition in the weld was about 30C lower than the transition temperature from standard CTOD bend-bar tests, and that transition temperature difference was predicted well. Hence surface cracks in girth welds may exhibit higher fracture resistance in full-scale behavior than might be predicted from CTOD bend-bar specimen testing. These limited tests show that with additional validation efforts the FITT Master Curve is appropriate for implementation to codes and standards for girth-weld defect stress-based criteria. For strain-based criteria or leak-before-break behavior, the pipeline would have to operate at some additional temperature above the FITT of the surface crack to ensure sufficient ductile fracture behavior.

scholarly journals The Increase in a Brittle-to-ductile Transition Temperature in Fe–Al Single Crystals

2011 ◽  
Vol 51 (6) ◽  
pp. 999-1004 ◽  
Author(s):  
Masaki Tanaka ◽  
Keiki Maeno ◽  
Kenji Higashida ◽  
Masahiro Fujikura ◽  
Kohsaku Ushioda
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
Brittle To Ductile Transition

scholarly journals A New Method for Determining the Brittle-to-Ductile Transition Temperature of a TiAl Intermetallic

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1550
Author(s):  
Sarper Nizamoglu ◽  
Karl-Heinz Lang ◽  
Stefan Guth ◽  
Martin Heilmaier
Keyword(s):  
Transition Temperature ◽  
Charpy Impact ◽  
Plastic Strain Amplitude ◽  
Bending Tests ◽  
Brittle To Ductile Transition ◽  
Intermetallic Materials ◽  
Different Temperatures ◽  
Specific Temperature ◽  
Increasing Temperature ◽  
Fully Lamellar

Intermetallic materials typically change their deformation behavior from brittle to ductile at a certain temperature called the Brittle-to-Ductile Transition Temperature (BDTT). This specific temperature can be determined by the Charpy impact, tensile or bending tests conducted at different temperatures and strain rates, which usually requires a large number of specimens. In order to reduce the number of necessary specimens for finding the BDTT, a new methodology comprising cyclic loadings as the crucial step was studied on a fully lamellar TiAl alloy with composition Ti-48Al-2Nb-0.7Cr-0.3Si. The loading blocks are applied isothermally under strain control and repeated on the same specimen at different temperatures. The development of plastic strain amplitude with increasing temperature is analyzed to determine the BDTT of the specimen. The BDTTs found with the described method agree well with literature data derived with conventional methods. With the loading strategy presented in this study, the BDTT and additionally the effect of strain rate on it can be found by using a single specimen.

Plastic Deformation Of AI-Cu-Fe Icosahedral Quasicrystals

1998 ◽  
Vol 553 ◽  
Author(s):  
E. Giacometti ◽  
N. Baluc ◽  
J. Bonneville
Keyword(s):  
Plastic Deformation ◽  
Transition Temperature ◽  
Flow Stress ◽  
Constant Strain Rate ◽  
Friction Stress ◽  
Plastic Strains ◽  
Total Flow ◽  
Brittle To Ductile Transition ◽  
Slip Bands ◽  
Icosahedral Quasicrystals

AbstractPoly-quasicrystalline specimens of the Al-Cu-Fe system have been pre-strained and further deformed at various temperatures, above and below the brittle-to-ductile transition temperature, under constant strain-rate conditions. The experiments have been specially designed to examine the respective contributions of the thermally reversible and structural dependent parts to the total flow stress. We show that the so-called internal stress, which results from the deformation builtin microstructure, has a rather low value, if any. In addition, the flow stress is found to be fully temperature reversible, if one takes into account previous plastic strains. We suggest that these results can be explained by a weakening of the friction stress, due to the formation of soft slip bands.

Application of Master Curve Method to Fracture Toughness Estimation of the Transport and Storage Cask Material

2008 ◽  
Author(s):  
Kiminobu Hojo ◽  
Kentaro Yoshimoto ◽  
Ryuichi Yamamoto ◽  
Toshihiro Matsuoka ◽  
Uwe Mayer
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Alloy Steel ◽  
Master Curve ◽  
Structural Integrity ◽  
Scale Model ◽  
Low Alloy Steel ◽  
Brittle To Ductile Transition ◽  
Data Scatter ◽  
And Storage

The transportation and storage casks have to be designed by considering transport and handling accidents. IAEA safety standard [1] requires drop test using a scale model and demonstration of structural integrity of the cask container vessel from the view point of leakage and instable fracture. For the fracture evaluation, it has to be verified that brittle fracture does not occur at the lowest temperature −40degC. MHI has developed the MSF-57BG cask whose body is made of forged low alloy steel LF3-m. It is well known that low alloy steel has the brittle-to-ductile transition temperature range of fracture toughness and large scatter of toughness value in this region. For the cask’s integrity evaluation, it is needed to obtain the fracture toughness dependent on temperature of this material by considering data scatter. The Master curve procedure [2] was proposed for estimation of fracture toughness of the pressure vessel on the basis of statistical procedure by using relatively small number of specimens. This paper examined the determination method of fracture toughness considering dynamic loading effect and data scatter in the brittle-to-ductile transition temperature by using the Master curve procedure.

Determination of Brittle-to-Ductile Transition Temperatures of Large-Diameter TMCP Linepipe Steel With High Charpy Energy by Use of Modified West Jefferson Testing

2016 ◽  
Author(s):  
Y. Hioe ◽  
G. Wilkowski ◽  
M. Fishman ◽  
M. Myers
Keyword(s):  
Transition Temperature ◽  
Brittle Fracture ◽  
Large Diameter ◽  
Pipe Steels ◽  
Line Pipe ◽  
Brittle To Ductile Transition ◽  
Pipe Burst ◽  
Drop Weight Tear Test ◽  
Fracture Appearance ◽  
Shear Area

In this paper the results will be presented for burst tests from a Joint Industry Project (JIP) on “Validation of Drop Weight Tear Test (DWTT) Methods for Brittle Fracture Control in Modern Line-Pipe Steels by Burst Testing”. The JIP members for this project were: JFE Steel as founding member, ArcelorMittal, CNPC, Dillinger, NSSMC, POSCO, Tenaris, and Tokyo Gas. Two modified West Jefferson (partial gas) pipe burst tests were conducted to assess the brittle-to-ductile transition temperature and brittle fracture arrestability of two 48-inch diameter by 24.6-mm thick X65 TMCP line-pipe steels. These steels had very high Charpy energy (350J and 400J) which is typical of many modern line-pipe steels. In standard pressed-notch DWTT specimen tests, these materials exhibited abnormal fracture appearance (ductile fracture from the pressed notch prior to brittle fracture starting) that occurs with many high Charpy energy steels. Such behavior makes the transition temperature difficult to determine. The shear area values versus temperature results for these two burst tests compared to various modified DWTT specimens are shown. Different rating methodologies; DNV, API, and a Best-Estimate of steady-state fracture propagation appearance were evaluated.

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