Temperature and Strain Rate Effects on Plastic Deformation of Titanium Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 3619-3624 ◽  
Author(s):  
K. Ogawa
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Titanium Alloys ◽  
Tensile Deformation ◽  
Beta Titanium Alloy ◽  
Stress Strain ◽  
Strain Rate Effects ◽  
Wide Range ◽  
Rate Effects ◽  
The Impact

Since titanium alloys are the most promising structural materials for the high velocity vehicles, the impact tensile strength of the materials is presently investigated. Three kinds of aging treatments on the beta-titanium alloy were performed, and the tensile deformation behaviors were identified in the wide range of the temperature and the strain rate. The stress－strain relations of the titanium alloy significantly depend on the temperature and the strain rate investigated. Thermally activated process concept was applied to explain the experimental results, and the stress-strain relations at high strain rates were well understood with taking account of adiabatic heating effect. It has been found that the stress-strain curves depend on the microstructures, while the temperature and the strain rate effects are almost independent of the different aging treatments.

A numerical assessment of strain rate effects on the critical state of crushable granular materials

2022 ◽  
Vol 12 (1) ◽  
pp. 1-19
Author(s):  
S.K. Das ◽  
S.K. Verma ◽  
A. Das
Keyword(s):  
Strain Rate ◽  
Granular Materials ◽  
Critical State ◽  
Triaxial Tests ◽  
Particle Crushing ◽  
Confining Stress ◽  
Stress Strain ◽  
Strain Rate Effects ◽  
Coral Sand ◽  
Rate Effects

The present study highlights the effects of strain rate on the critical state response of crushable granular materials. A set of drained triaxial tests is simulated using the discrete element method (DEM) to understand the rate effects on the stress-strain and volumetric behaviour of the granular sample. The DEM parameters are obtained by comparing the stress-strain and particle crushing behaviour of in-house experimental analysis on crushable coral sand under a slow strain rate. In DEM, the particles are subjected to varied strain rates under different initial confining pressures and initial densities to capture the rate effects on the macroscopic responses until the critical state. It is seen that crushing increases with increasing confining stress. However, a higher strain rate induces relatively lower crushing and higher strength in terms of both peak stress and residual stress. It is observed that in pressure-volume space, the critical state line alters with the increasing strain rate of the crushable samples, especially at high confining conditions, whereas strain rate effect on critical state seems to be negligible at low confining conditions due to the absence of particle crushing.

A Thermo-Viscoplastic Constitutive Equation Based on Hyperbolic-Shape Thermo-Activated Barriers

1984 ◽  
Vol 106 (4) ◽  
pp. 331-336 ◽  
Author(s):  
Li-Lih Wang
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Present Model ◽  
Strain Rate Effects ◽  
Bcc Metals ◽  
Special Cases ◽  
Wide Range ◽  
Rate Effects ◽  
Simple Parameter ◽  
Good Agreement

A thermo-viscoplastic constitutive equation is proposed on the basis of thermoactivated mechanism with a spectrum of hyperbolic-shape barriers, suitable for a wide range of strain rate and temperature. Relations with other existing models or rate theories, which may be regarded a special cases of present model, are examined. Good agreement with experimental data for both fcc and bcc metals is shown. The activation volume is found dependent on temperature according to an exponential law. A simple parameter, which describes the equivalence between strain rate effects and temperature effects on flow stress, is suggested similar to Zener-Hollomon parameters

Strain-Rate Effects in the Dynamic Buckling of a Simple Elastic-Plastic Model

1997 ◽  
Vol 64 (1) ◽  
pp. 193-200 ◽  
Author(s):  
D. Karagiozova ◽  
N. Jones
Keyword(s):  
Strain Rate ◽  
Plastic Material ◽  
Rate Sensitivity ◽  
Dynamic Buckling ◽  
Strain Rate Effects ◽  
Plastic Model ◽  
Elastic Plastic ◽  
Rate Effects ◽  
Elastic Plastic Material ◽  
The Impact

The phenomenon of dynamic buckling is examined when the influence of material strain-rate sensitivity is retained in the basic equations for a simple elastic-plastic model with linear strain hardening when subjected to an impact by a mass. Two approaches are proposed for taking into account the material strain-rate effects and both use the Cowper-Symonds constitutive equation. The critical impact velocities depend on the impact mass and are determined for a wholly elastic material, a strain-rate insensitive elastic-plastic material and an elastic-plastic material with a dynamic yield force together with linear or nonlinear hardening due to the strain-rate effects. The results obtained show that both strain-rate sensitive models predict impact velocities which are higher than those predicted by the strain-rate insensitive idealization and that the influence of any initial imperfections is important for the three material models considered.

Microstructure and Texture in an Alpha/Beta Titanium Alloy and their Impact on Mechanical Response

2007 ◽  
Vol 539-543 ◽  
pp. 3589-3594
Author(s):  
W.J. Evans ◽  
F.R. Eng
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Titanium Alloys ◽  
Plane Strain ◽  
Basal Plane ◽  
Mechanical Response ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Strain And Strain Rate ◽  
Alpha Beta

The paper explores texture in the titanium alloys Ti-6-4 and Ti 550. It illustrates how texture evolves under plane strain compression in Ti-6-4. This evolution is dependent on temperature, degree of reduction (strain) and strain rate. Rolled (Ti-6-4) and forged (Ti 550) variants with different textures are then examined under tension and torsion loading in relation to their monotonic and fatigue response. Correlation of the observations with regard to orientation of the basal plane is demonstrated.

Effects of Strain Rate on the Tensile Deformation of Single-Crystal Copper Films

2011 ◽  
Vol 675-677 ◽  
pp. 671-673 ◽  
Author(s):  
Shuang Xu ◽  
Ya Fang Guo
Keyword(s):  
Strain Rate ◽  
Single Crystal ◽  
Tensile Deformation ◽  
Md Simulations ◽  
Copper Films ◽  
Strain Rate Effects ◽  
Single Crystal Copper ◽  
Cu Films ◽  
Rate Effects ◽  
Eam Potential

Molecular dynamics (MD) simulations with an EAM potential are carried out to study the strain rate effects on the tensile deformation of single-crystal copper films. The stress, the atomic energy, as well as the atomic configurations of the systems are presented to explore the strain rate effects on copper films. It is found that yield stress increases with loading rate. Meanwhile, deformation mechanisms with different strain rates are analyzed in the present work. At lower strain rate, slips along {111} planes are primarily responsible for the plastic deformation in nano-Cu films. As strain rate increased, the motion of dislocations becomes easier, a transition of the deformation mechanism from sequential propagation of slips along well-defined slip planes to complex cross-slip.

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