Experimental Basis for Temperature-Dependent Viscoplastic Constitutive Equations

1990 ◽  
Vol 43 (5S) ◽  
pp. S338-S344 ◽  
Author(s):  
U. S. Lindholm
Keyword(s):  
Strain Rate ◽  
Constitutive Models ◽  
Inelastic Strain ◽  
Time Dependent ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Experimental Basis ◽  
Temperature Dependent ◽  
Evolutionary Equations ◽  
Nonproportional Loading

In this paper the author reviews experimental data which is felt to be illustrative of time-dependent, high temperature deformation of metals and, therefore, instructive for the development of constitutive models. Issues addressed are the interrelation between time (strain rate) and temperature, the development of evolutionary equations for both isotropic and directional hardening and recovery, and the orientation of the inelastic strain rate with respect to stress during nonproportional loading.

Extensive Modeling of High-Temperature Deformation Based on Unified Approach

1993 ◽  
Vol 115 (1) ◽  
pp. 91-92
Author(s):  
T. Nakamura ◽  
Y. Asada
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
High Temperature ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Inelastic Deformation ◽  
Inelastic Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Unified Approach

A unified inelastic constitutive equation is proposed to describe the cyclic inelastic deformation of 2 1/4Cr-1Mo steel at 550°C. In the present study, an evolution of the overstress is discussed which leads the time-independent term into the inelastic strain rate. A mathematical model is developed and some examples of the numerical simulation are presented.

High Temperature Deformation Mechanism Maps of NiAl

2004 ◽  
Vol 449-452 ◽  
pp. 57-60
Author(s):  
I.G. Lee ◽  
A.K. Ghosh
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Calculation Method ◽  
Deformation Behavior ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
Temperature Strain

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.

Characterization of High Temperature Deformation Behavior of BFe10-1-2 Cupronickel Alloy Using Orthogonal Analysis

2017 ◽  
Vol 36 (7) ◽  
pp. 701-710
Author(s):  
Jun Cai ◽  
Kuaishe Wang ◽  
Xiaolu Zhang ◽  
Wen Wang
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Statistical Parameters ◽  
Orthogonal Analysis

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.

scholarly journals Hot Deformation Behavior and Microstructure Evolution of Cu–Ni–Co–Si Alloys

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2042 ◽  
Author(s):  
Feng Liu ◽  
Jimiao Ma ◽  
Lijun Peng ◽  
Guojie Huang ◽  
Wenjing Zhang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Strain Rate Range ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Hot Deformation Behavior ◽  
Deformation Activation Energy ◽  
The Matrix ◽  
Dynamic Recrystallization Behavior

The Cu-1.7Ni-1.4Co-0.65Si (wt%) alloy is hot compressed by a Gleeble-1500D machine under a temperature range of 760 to 970 °C and a strain rate range of 0.01 to 10 s−1. The flow stress increases with the extension of strain rate and decreases with the rising of deformation temperature. The dynamic recrystallization behavior happens during the hot compression deformation process. The hot deformation activation energy of the alloy can be calculated as 468.5 kJ/mol, and the high temperature deformation constitutive equation is confirmed. The hot processing map of the alloy is established on the basis of hot deformation behavior and hot working characteristics. With the optimal thermal deformation conditions of 940 to 970 °C and 0.01 to 10 s−1, the fine equiaxed grain and no holes are found in the matrix, which can provide significant guidance for hot deformation processing technology of Cu–Ni–Co–Si alloy.

High-Temperature Deformation of Magnesium ElektronTM 43

2012 ◽  
Vol 735 ◽  
pp. 93-100
Author(s):  
Alexander J. Carpenter ◽  
Anthony J. Barnes ◽  
Eric M. Taleff
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Superplastic Forming ◽  
Solute Drag ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained ◽  
Boundary Sliding

Complex sheet metal components can be formed from lightweight aluminum and magnesium sheet alloys using superplastic forming technologies. Superplastic forming typically takes advantage of the high strain-rate sensitivity characteristic of grain-boundary-sliding (GBS) creep to obtain significant ductility at high temperatures. However, GBS creep requires fine-grained materials, which can be expensive and difficult to manufacture. An alternative is provided by materials that exhibit solute-drag (SD) creep, a mechanism that also produces elevated values of strain-rate sensitivity. SD creep typically operates at lower temperatures and faster strain rates than does GBS creep. Unlike GBS creep, solute-drag creep does not require a fine, stable grain size. Previous work by Boissière et al. suggested that the Mg-Y-Nd alloy, essentially WE43, deforms by SD creep at temperatures near 400°C. The present investigation examines both tensile and biaxial deformation behavior of ElektronTM 43 sheet, which has a composition similar to WE43, at temperatures ranging from 400 to 500°C. Data are presented that provide additional evidence for SD creep in Elektron 43 and demonstrate the remarkable degree of biaxial strain possible under this regime (>1000%). These results indicate an excellent potential for producing complex 3-D parts, via superplastic forming, using this particular heat-treatable Mg alloy.

High Temperature Deformation Mechanisms and Processing Map for Hot Working of Cast-Homogenized Mg-3Sn-2Ca Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 3616-3621 ◽  
Author(s):  
K.P. Rao ◽  
Y.V.R.K. Prasad ◽  
Norbert Hort ◽  
Karl Ulrich Kainer
Keyword(s):  
Strain Rate ◽  
Processing Map ◽  
Volume Fraction ◽  
Flow Instability ◽  
Back Stress ◽  
Hot Working ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Compression Tests

The hot working behavior of Mg-3Sn-2Ca alloy has been investigated in the temperature range 300–500 oC and strain rate range 0.0003–10 s-1, with a view to evaluate the mechanisms and optimum parameters of hot working. For this purpose, a processing map has been developed on the basis of the flow stress data obtained from compression tests. The stress-strain curves exhibited steady state behavior at strain rates lower than 0.01 s-1 and at temperatures higher than 350 oC and flow softening occurred at higher strain rates. The processing map exhibited two dynamic recrystallization domains in the temperature and strain rate ranges: (1) 300–420 oC and 0.0003–0.003 s-1, and (2) 420–500 oC and 0.003–1.0 s-1, the latter one being useful for commercial hot working. Kinetic analysis yielded apparent activation energy values of 161 and 175 kJ/mole in domains (1) and (2) respectively. These values are higher than that for self-diffusion in magnesium suggesting that the large volume fraction of intermetallic particles CaMgSn present in the matrix generates considerable back stress. The processing map reveals a wide regime of flow instability which gets reduced with increase in temperature or decrease in strain rate.

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