Modelling high temperature deformation of lamellar TiAl crystal using strain-rate enhanced crystal plasticity

2020 ◽  
Vol 788 ◽  
pp. 139524
Author(s):  
M. Umer Ilyas ◽  
M. Rizviul Kabir
2004 ◽  
Vol 449-452 ◽  
pp. 57-60
Author(s):  
I.G. Lee ◽  
A.K. Ghosh

In order to analyze high temperature deformation behavior of NiAl alloys, deformation maps were constructed for stoichiometric NiAl materials with grain sizes of 4 and 200 µm. Relevant constitute equations and calculation method will be described in this paper. These maps are particularly useful in identifying the location of testing domains, such as creep and tensile tests, in relation to the stress-temperature-strain rate domains experienced by NiAl.


2017 ◽  
Vol 36 (7) ◽  
pp. 701-710
Author(s):  
Jun Cai ◽  
Kuaishe Wang ◽  
Xiaolu Zhang ◽  
Wen Wang

AbstractHigh temperature deformation behavior of BFe10-1-2 cupronickel alloy was investigated by means of isothermal compression tests in the temperature range of 1,023~1,273 K and strain rate range of 0.001~10 s–1. Based on orthogonal experiment and variance analysis, the significance of the effects of strain, strain rate and deformation temperature on the flow stress was evaluated. Thereafter, a constitutive equation was developed on the basis of the orthogonal analysis conclusions. Subsequently, standard statistical parameters were introduced to verify the validity of developed constitutive equation. The results indicated that the predicted flow stress values from the constitutive equation could track the experimental data of BFe10-1-2 cupronickel alloy under most deformation conditions.


1996 ◽  
Vol 11 (6) ◽  
pp. 1433-1439 ◽  
Author(s):  
Anne Vilette ◽  
S. L. Kampe

Cubic (δ) bismuth oxide (Bi2O3) has been subjected to high temperature deformation over a wide range of temperatures and strain rates. Results indicate that bismuth oxide is essentially incapable of plastic deformation at temperatures below the monoclithic to cubic phase transformation which occurs at approximately 730 °C. Above the transformation temperature, however, Bi2O3 is extensively deformable. The variability of flow stress to temperature and strain rate has been quantified through the determination of phenomenological-based constitutive equations to describe its behavior at these high temperatures. Analysis of the so-determined deformation constants indicate an extremely strong sensitivity to strain rate and temperature, with values of the strain-rate sensitivity approaching values commonly cited as indicative of superplastic behavior.


2008 ◽  
Vol 22 (31n32) ◽  
pp. 6016-6021 ◽  
Author(s):  
K. A. LEE ◽  
J. NAMKUNG ◽  
M. C. KIM

The effect of high temperature deformation on the low thermal expansion property of Fe -29 Ni -17 Co alloy was investigated in the compressive temperature range of 900~1300°C at a strain rate range of 25 ~ 0.01 sec. -1. The thermal expansion coefficient (α30~400) generally increased with increasing compressive temperature. In particular, α30~400 increased remarkably as the strain rate decreased at temperatures above 1100°C. Note, however, that α30~400 at low compressive temperatures (900°C and 1000°C) increased abnormally at high strain rates. Based on the investigation of various possibilities of change in low thermal expansion behavior, the experimental results indicated that both the appearance of the α phase and evolution of grain size due to hot compression clearly influenced the low thermal expansion behavior of this invar-type alloy. The correlation between the microstructural cause and invar phenomena and theoretical explanation for the low thermal expansion behavior of Fe -29% Ni -17% Co were also suggested.


2014 ◽  
Vol 922 ◽  
pp. 807-812 ◽  
Author(s):  
Robert Werner ◽  
Emanuel Schwaighofer ◽  
Martin Schloffer ◽  
Helmut Clemens ◽  
Janny Lindemann ◽  
...  

In the present study the high-temperature deformation behavior of a caste and subsequently HIPed β-solidifying γ-TiAl-based alloy with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at. %), termed TNM alloy, is investigated. At room temperature this alloy consists of ordered γ-TiAl, α2-Ti3Al and βo-TiAl phases. By increasing the temperature, α2and βodisorder to α and β, respectively. In order to get a better understanding of dynamic recovery and recrystallization processes during thermomechanical processing, isothermal compression tests on TNM specimens are carried out on a Gleeble®3500 simulator. These tests are conducted at temperatures ranging from 1100 °C to 1250 °C (in the α/α2+β/βo+γ phase field region) applying strain rates in the range of 0.005 s-1to 0.5 s-1up to a true strain of 0.9. The evolution of microstructure along with the dynamically recrystallized grain size during hot deformation is examined by scanning electron microscopy (SEM). The flow softening behavior after reaching the peak stress in the true stress-true strain curve is attributed to dynamic recrystallization. By using the Zener-Hollomon parameter as a temperature-compensated strain rate the dependence of flow stress on temperature and strain rate is shown to follow a hyperbolic-sine Arrhenius-type relationship.


2012 ◽  
Vol 182-183 ◽  
pp. 189-193
Author(s):  
Ting Qu Li ◽  
M. Gao ◽  
S.H. Wang ◽  
Zhan Yi Cao

In this paper, the high temperature tensile properties of the LAZ532-2RE alloy prepared by hot extruded processing after vacuum casting was investaged. The tensile properties of the extruded LAZ532-2RE alloy specimens were tested at different temperature with different strain rate. The microstructures near the fractured surfaces were observed using microscope in order to investigate the dominant deformation mechanism. The activation energy was calculated to explain the high temperature deformation mechanism. The result indicated that the strength of LAZ532-2RE alloy was high at the temperature range from 398K to 423K. Meanwhile, the fracture elongation of the alloy reaches 121% at 523K under strain rate 1×10-3s-1.


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