High-temperature Deformation Kinetics of Gold at 473K to 773K

2008 ◽  
Vol 1137 ◽  
Author(s):  
Vineet Bhakhri ◽  
Robert J. Klassen
Keyword(s):  
High Temperature ◽  
Cell Structure ◽  
Dislocation Cell ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Indentation Creep ◽  
Creep Tests ◽  
Dislocation Glide ◽  
Deformation Kinetics ◽  
Temperature Constant

AbstractHigh-temperature constant-force indentation creep tests of 200 seconds duration were performed on an annealed gold specimen at 473K to 773K, to investigate the dependence of the micro-/nano-indentation deformation kinetics upon indentation stress, temperature and time. The indent stress displayed a clear indentation size effect at 473 K. An analysis of the measured indentation creep rate, and its dependence upon temperature and stress, indicate that the strength of the deformation rate limiting obstacles increases with temperature. This is consistent with the expected temperature dependent evolution of the dislocation cell structure whose boundaries become the primary obstacles to dislocation glide.

Analysis of Intragranular Misorientation Related to Deformation in an Al-Mg-Mn Alloy

2005 ◽  
Vol 495-497 ◽  
pp. 1049-1054 ◽  
Author(s):  
Yoshimasa Takayama ◽  
Jerzy A. Szpunar ◽  
Hajime Kato
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Room Temperature ◽  
Electron Back Scatter Diffraction ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Stored Energy ◽  
Kernel Average Misorientation ◽  
Dislocation Glide ◽  
Scanning Electron

Intragranular misorientation reflects strain generated during deformation with dislocation glide. The SEM/EBSP (scanning electron microscope/ electron back scatter diffraction pattern) technique provides is “kernel average misorientation (KAM)” as the most appropriate quantity to evaluate the strain or the stored energy for a given point. The KAM is defined for a given point as the average misorientation of that point with all of its neighbors. In the present paper two analyses of the intragranular misorientation using the SEM/EBSP technique for a cyclic deformation at room temperature and a high temperature deformation in an Al-Mg-Mn alloy are reviewed.

Effect of Texture on High Temperature Deformation Behaviors of Ti-6Al-4V Alloy

2007 ◽  
Vol 340-341 ◽  
pp. 835-840 ◽  
Author(s):  
J.E. Park ◽  
J.B. Jeon ◽  
S. Lee Semiatin ◽  
Chong Soo Lee ◽  
Young Won Chang
Keyword(s):  
High Temperature ◽  
Rolling Process ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Internal Variables ◽  
Creep Tests ◽  
Ti Alloys ◽  
Deformation Behaviors ◽  
Texture Effect ◽  
Hot Rolled

Textures developed during hot rolling process may affect the high temperature deformation behaviors of Ti alloys, but their relation has not been well understood or quantitatively analyzed yet. A series of load relaxation and creep tests for hot rolled Ti-6Al-4V alloy has been conducted in this work to clarify the effect of textures on the deformation behaviors of the alloy under 700 °C and the result was analyzed by using an internal variables approach. The internal strength σ* was found to vary significantly by the textures, but not by the temperature change, while the texture effect was found to decrease at higher temperatures.

Dislocation Creep in Al-22.2, 53.6 and 101 at.ppm Fe Solid Solution Alloys

2014 ◽  
Vol 922 ◽  
pp. 749-754
Author(s):  
K. Takeshima ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Creep Resistance ◽  
Dislocation Creep ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Stress Range ◽  
Creep Tests ◽  
Ultra High Purity ◽  
Dominant Deformation Mechanism

Creep tests of ultra-high-purity (99.999%) Al and Al-22.2, 53.6, 101 at.ppm Fe solid solution alloys were conducted at 773 K in the stress range of 2-6 MPa in order to investigate effect of solute Fe on high temperature deformation of Al. Creep resistance was enhanced by addition of Fe in solid solution. The stress exponents of the samples exhibited values of about 5, which indicate that climb-controlled dislocation creep was dominant deformation mechanism. It could be suggested that Fe atoms segregating in dislocations due to the strong interaction between solute Fe atoms and the dislocation enhanced the creep resistance.

Effects of Microstructure Evolution on High-Temperature Mechanical Deformation of 95Sn-5Sb

2008 ◽  
Author(s):  
Harry Schoeller ◽  
Shubhra Bansal ◽  
Aaron Knobloch ◽  
David Shaddock ◽  
Junghyun Cho
Keyword(s):  
High Temperature ◽  
Lead Free ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Second Phase ◽  
Creep Tests ◽  
Well Drilling ◽  
Deep Well ◽  
High Homologous Temperature ◽  
Lead Free Solders

Lead-free solders have garnered much attention in recent years due to legislation banning the use of lead in electronics. As use of lead solders is phased out, there is a need for lead-free alternatives for niche applications such as high temperature environments where traditionally high lead solders are used. Electronics and sensors exposed to high-temperature environments such as those associated with deep well drilling require solder interconnects that can withstand high thermal-mechanical stresses. In an effort to characterize solder alloys for such applications, this study focuses on deformation behavior of the Sn95-Sb5 solder under high-temperature exposures (from 298°K to 473°K). As compared to conventional high-temperature Pb-based solder 90Pb–10Sn, Sn95–Sb5 exhibited very high tensile strength and modulus, as well as superior creep properties despite its lower melting temperature. Importantly, high-temperature deformation was shown to be influenced by the presence of the second phase (SnSb) distributed within the Sn-rich matrix. These second phase precipitates appeared to be dissolved into the Sn-rich phase above 453°K, which converted the solder into a single-phase alloy and resulted in a change in its deformation mechanism. Furthermore, as the service temperature is of such high homologous temperature (T > 0.5Tm), creep deformation will contribute significantly toward the life of the solder joint during thermal cycling. In order to characterize the creep behavior and to identify controlling mechanism(s), creep tests were carried out, from which the stress exponent and activation energy were determined. In this study, detailed microstructures under high-temperature are presented in conjunction with the corresponding mechanical behavior to further understand the controlling deformation mechanisms.

On the High Temperature Creep and Relaxation Behaviour of Zr-based Bulk Metallic Glasses

2000 ◽  
Vol 644 ◽  
Author(s):  
B. S. S. Daniel ◽  
M. Heilmaier ◽  
A. Reger-Leonhard ◽  
J. Eckert ◽  
L. Schultz
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Behaviour ◽  
True Strain ◽  
Constant Load ◽  
Strain Rate Range ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Creep Tests ◽  
True Strain Rate

AbstractCreep tests under constant load as well as constant true strain rate were carried out at near the glass transition temperatures (Tg) to study the time dependent flow behaviour of a Zr-based bulk metallic glass (BMG). The strain rate - stress relation over a wide strain rate-range (10-7 to 10-2 s-1) was established for different temperatures. The high temperature deformation behaviour is explained on the basis of stress induced creation of free volume versus diffusion controlled annihilation processes. It was found that the creep kinetics near Tg is controlled by the mobility of atoms with an activation energy value Q =410kJ/mol.

scholarly journals Investigation of nucleation processes during dynamic recrystallization of ice using cryo-EBSD

2017 ◽  
Vol 375 (2086) ◽  
pp. 20150345 ◽  
Author(s):  
T. Chauve ◽  
M. Montagnat ◽  
F. Barou ◽  
K. Hidas ◽  
A. Tommasi ◽  
...  
Keyword(s):  
High Temperature ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Creep Tests ◽  
Spontaneous Nucleation ◽  
Kink Bands ◽  
Nucleation Mechanisms ◽  
The Impact

Nucleation mechanisms occurring during dynamic recrystallization play a crucial role in the evolution of microstructures and textures during high temperature deformation. In polycrystalline ice, the strong viscoplastic anisotropy induces high strain heterogeneities between grains which control the recrystallization mechanisms. Here, we study the nucleation mechanisms occurring during creep tests performed on polycrystalline columnar ice at high temperature and stress ( T =−5°C; σ =0.5 MPa) by post-mortem analyses of deformation microstructures using cryogenic electron backscatter diffraction. The columnar geometry of the samples enables discrimination of the nuclei from the initial grains. Various nucleation mechanisms are deduced from the analysis of the nuclei relations with the dislocation sub-structures within grains and at grain boundaries. Tilt sub-grain boundaries and kink bands are the main structures responsible for development of polygonization and mosaic sub-structures. Nucleation by bulging at serrated grain boundaries is also an efficient nucleation mechanism near the grain boundaries where strain incompatibilities are high. Observation of nuclei with orientations not related to the ‘parent’ ones suggests the possibility of ‘spontaneous’ nucleation driven by the relaxation of the dislocation-related internal stress field. The complexity of the nucleation mechanisms observed here emphasizes the impact of stress and strain heterogeneities on dynamic recrystallization mechanisms. This article is part of the themed issue ‘Microdynamics of ice’.

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