The Effect of Strain Rate and Temperature on Yielding in Steels

1972 ◽  
Vol 94 (1) ◽  
pp. 207-212 ◽  
Author(s):  
D. P. Kendall
Keyword(s):  
Yield Strength ◽  
Mild Steel ◽  
Strain Rate ◽  
Maraging Steel ◽  
Elastic Strain ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Aging Effects ◽  
Increasing Temperature

The effect of elastic strain rates ranging from 10−14 to 10 sec−1 and temperatures ranging from 200 K (−100 F) to 590 K (600 F) on the yield strength of several steels is reported. The steels utilized are a 1018 mild steel, 4340 steel, H-11 tool steel, and 300 grade maraging steel. The results are interpreted in terms of the Cottrell-Bilby yielding model based on release of dislocations from locking carbon atmospheres. The results for all of the materials except the maraging steel are consistent with this model if it is modified to account for relocking of dislocations by migration of carbon atoms. The maraging steel shows a constant strain rate sensitivity at a constant temperature, over the range of strain rates investigated. This rate sensitivity decreases with increasing temperature and at 590 K (600 F) a decreasing strength with increasing strain rate is found. This is attributed to stress aging effects.

Strain rate sensitivity of a mild steel at room temperature and strain rates of up to 105s−1

1980 ◽  
Vol 15 (4) ◽  
pp. 201-207 ◽  
Author(s):  
M S J Hashmi
Keyword(s):  
Finite Difference ◽  
Mild Steel ◽  
Strain Rate ◽  
Strain Hardening ◽  
Strain Rate Sensitivity ◽  
Elastic Strain ◽  
Room Temperature ◽  
Numerical Technique ◽  
Rate Sensitivity ◽  
Strain Rates

Experimental results on a mild steel are reported from ballistics tests which gave rise to strain rates of up to 105 s−1. A finite-difference numerical technique which incorporates material inertia, elastic-strain hardening and strain-rate sensitivity is used to establish the strain-rate sensitivity constants p and D in the equation, σ4 = σ1 (1+(∊/D)1/ p). The rate sensitivity established in this study is compared with those reported by other researchers.

THE MECHANICAL BEHAVIOUR OF COBALT SUPERALLOYS WITH TI ELEMENT ADDITION

2013 ◽  
Vol 37 (3) ◽  
pp. 365-373
Author(s):  
Tao-Hsing Chen
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
Rate Sensitivity ◽  
Material Testing ◽  
Testing System ◽  
Strain Rates ◽  
Strengthening Effect ◽  
Microstructural Characteristics ◽  
Element Addition ◽  
Increasing Temperature

The influence of titanium element, strain rate and tested temperatures on the mechanical properties and microstructural characteristics will be investigated in this paper. These cobalt-based superalloys are tested using material testing system (MTS) at strain rates of 10−3, 10−2 and 10−1 s−1 and at temperatures of 700, 500 and 25° C, respectively. It is found that the flow stress increases with increasing strain rate and Ti, but decreases with increasing temperature. Furthermore, the strain rate sensitivity increases with increasing strain rate, but decreases with increasing temperature. The microstructural observations confirm that the mechanical response of the cobalt superalloy specimens is directly related to the effects of the titanium contents, strain rate and temperature on the evolution of the microstructure. It can be observed that the strengthening effect in cobalt-based superalloys is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature.

scholarly journals Strain-controlled bulge test

2008 ◽  
Vol 23 (12) ◽  
pp. 3295-3302 ◽  
Author(s):  
B. Erdem Alaca ◽  
K. Bugra Toga ◽  
Orhan Akar ◽  
Tayfun Akin
Keyword(s):  
Strain Rate ◽  
Rate Control ◽  
Closed Loop ◽  
Temporal Evolution ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Bulge Test ◽  
Strain Rates ◽  
Strain Formulation ◽  
Control Criterion

A closed-loop approach is adopted to implement strain rate control during the bulge test. Due to the difficulty of measuring strains directly, the technique is based on the conversion of displacement measurements to the corresponding strains using the plane-strain formulation. The necessary temporal evolution of the midpoint displacement of a rectangular diaphragm is derived under the condition of constant strain rate and is imposed as a control criterion. The technique is demonstrated on 500-nm-thick Au diaphragms by applying strain rates ranging from 2 × 10−6 to 2 × 10−4 s–1. By measuring the corresponding yield strength values, a strain rate sensitivity of 0.11 is obtained, which is close to what was previously reported on similar specimens using the microbending test.

On the Effect of Strain Rate and Temperature on the Yield Strength Anomaly in L21-structured Fe2AlMn

2008 ◽  
Vol 1128 ◽  
Author(s):  
Markus W. Wittmann ◽  
Janelle M. Chang ◽  
Yifeng Liao ◽  
Ian Baker
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Single Crystals ◽  
Yield Stress ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Temperature Range ◽  
Effects Of Temperature ◽  
Increasing Temperature

AbstractThe effects of strain rate and temperature on the yield strength of near-stoichiometric Fe2AlMn single crystals were investigated. In the temperature range 600-800K the yield stress increased with increasing temperature, a response commonly referred to as a yield strength anomaly. No strain rate sensitivity was observed below 750K, but at higher temperatures the yield stress increased with increasing strain rate. Possible mechanisms to explaining the effects of temperature and strain rate are discussed.

On the Strain Rate- and Temperature-Dependent Tensile Behavior of Eutectic Sn–Pb Solder

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
B. L. Boyce ◽  
L. N. Brewer ◽  
M. K. Neilsen ◽  
M. J. Perricone
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Morphological Changes ◽  
Thermal Strain ◽  
Rate Sensitivity ◽  
Microstructural Characterization ◽  
Grain Boundary Sliding ◽  
Tensile Behavior ◽  
Strain Rates

The present study examines the thermomechanical strain-rate sensitivity of eutectic 63Sn–37Pb solder over a broad range of strain-rates from 0.0002 s–1 to 200 s–1, thus encompassing failure events between 1 h and 1 ms, at temperatures ranging from −60 °C to + 100 °C. A newly developed servohydraulic tensile method enabled this broad range of strain-rates to be evaluated by a single technique, eliminating ambiguity caused by evaluation across multiple experimental methods. Two solder conditions were compared: a normalized condition representing a solder joint that has largely stabilized ∼30 days after solidification and an aged condition representing ∼30 years at near-ambient temperatures. The tensile behavior of both conditions exhibited dramatic temperature and strain-rate sensitivity. At 100 °C, the yield strength increased from 5 MPa at 0.0002 s–1 to 42 MPa at 200 s–1, while at −60 °C, the yield strength increased from 57 MPa at 0.0002 s–1 to 71 MPa at 200 s–1. The room temperature strain rate-dependent behavior was also measured for the lead free SAC396 alloy. The SAC alloy exhibited thermal strain-rate sensitivity similar to Sn–Pb over this temperature and strain-rate regime. Microstructural characterization using backscatter electron imaging and electron backscatter diffraction showed distinct, morphological changes of the microstructure for different thermomechanical conditions as well as some systematic changes in the crystallographic texture. However, very little intergranular rotation was observed over the range of thermomechanical conditions, suggesting the dominance of a grain boundary sliding (GBS) deformation mechanism. Finally, a recently developed unified-creep-plasticity constitutive model for solder deformation was found to describe the observed behavior with much higher fidelity than the common Johnson–Cook model.

Investigation of the Hot Deformation Behavior of an Al-Mg-Sc-Zr Alloy under Plane Strain Condition

2014 ◽  
Vol 611-612 ◽  
pp. 76-83 ◽  
Author(s):  
Johannes Taendl ◽  
Martina Dikovits ◽  
Cecilia Poletti
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Hot Deformation Behavior ◽  
Flow Curves ◽  
Increasing Temperature ◽  
Zr Alloy

This study investigates the hot deformation behavior of a new Al-Mg-Sc-Zr alloy under plane strain conditions. Flow curves corrected for deformation heating were calculated for strain rates between 0.01 and 10s-1 in a temperature range of 200 to 400°C. To evaluate the deformation behavior, strain rate sensitivity as well as flow localization parameter maps were calculated for strains of 0.2, 0.4, and 0.6. In addition, microstructural investigations and hardness measurements were performed for selected samples. It was shown that the flow stress decreased with deacreasing strain rate and increasing temperature. The best formability was observed for high strain rates and low temperatures as well as for low strain rates and high temperatures. In these cases no flow instabilities were observed.

Enhanced Plasticity of WE54/SiC Composite Prepared by Powder Metallurgy

2011 ◽  
Vol 465 ◽  
pp. 419-422 ◽  
Author(s):  
Zoltán Száraz ◽  
Zuzanka Trojanová
Keyword(s):  
Powder Metallurgy ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
High Strain ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Strain Rates ◽  
Deformation Characteristics ◽  
Powder Metallurgy Technique

The deformation characteristics of the WE54 magnesium alloy reinforced by 13% of SiC particles have been investigated in tension at elevated temperatures. Composite material was prepared by powder metallurgy technique. The strain rate sensitivity parameter m has been estimated by the abrupt strain rate changes (SRC) method. SRC tests and tensile tests with constant strain rate ( ) were performed at temperatures from 350 to 500 °C. Increased ductility has been found at high strain rates. The corresponding m value was 0.3. The activation energy Q has been estimated. Microstructure evolution has been observed by the light microscope and scanning electron microscope.

The Influence of Ti and Al Additions on the Mechanical Response of Cobalt Superalloy

2013 ◽  
Vol 284-287 ◽  
pp. 235-240
Author(s):  
Tao Hsing Chen
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
Rate Sensitivity ◽  
Testing System ◽  
Strain Rates ◽  
Strengthening Effect ◽  
Microstructural Properties ◽  
Al Additions ◽  
Increasing Temperature ◽  
Cobalt Base

The effect of titanium and aluminum contents, strain, strain rate and tested temperatures on the mechanical properties and microstructural properties will be investigated in this study. These cobalt base super alloys are to be tested using material testing system (MTS) at strain rates of 10-3, 10-2 and 10-1s-1 and at temperatures of 700°C, 500°C and 25°C respectively. It is found that the flow stress increases with increasing strain rate and Ti and Al contents, but decreases with increasing temperature. Furthermore, the strain rate sensitivity increases with increasing strain rate, but decreases with increasing temperature. The microstructural observations confirm that the mechanical response of the cobalt superalloy specimens is directly related to the effects of the titanium and aluminum contents, strain rate and temperature on the evolution of the microstructure. It can be observed that the strengthening effect in cobalt suprealloy is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature.

scholarly journals Effects of Cu Addition on Mechanical Behaviour, Microstructural Evolution and Anti-Corrosion Performance of TiAl-Based Intermetallic Alloy under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5056
Author(s):  
Cheng-Hsien Kuo ◽  
Tao-Hsing Chen ◽  
Ting-Yang Zeng
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Fracture Strain ◽  
Split Hopkinson Pressure Bar ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Phase Content ◽  
Corrosion Performance ◽  
Hopkinson Pressure Bar

TiAl-based intermetallic alloys are prepared with Cu concentrations of 3–5 at.% (atomic ratio). The mechanical properties and microstructural characteristics of the alloys are investigated under static and dynamic loading conditions using a material testing system (MTS) and split-Hopkinson Pressure Bar (SHPB), respectively. The electrochemical properties of the various alloys are then tested in Ringer’s solution. It is shown that the level of Cu addition significantly affects both the flow stress and the ductility of the samples. For Cu contents of 3 and 4 at.%, respectively, the flow stress and strain rate sensitivity increase at higher strain rates. Furthermore, for a constant strain rate, a Cu content of 4 at.% leads to an increased fracture strain. However, for the sample with the highest Cu addition of 5 at.%, the flow stress and fracture strain both decrease. The X-ray diffraction (XRD) patterns and optical microscopy (OM) images reveal that the lower ductility is due to the formation of a greater quantity of γ phase in the binary TiAl alloy system. Among all the specimens, that with a Cu addition of 4 at.% has the best anti-corrosion performance. Overall, the results indicate that the favourable properties of the TiAlCu4 sample stem mainly from the low γ phase content of the microstructure and the high α2 phase content.

The effects of strain and strain rate on residual microstructures in copper

1986 ◽  
Vol 44 ◽  
pp. 420-421
Author(s):  
M. F. Stevens ◽  
P. S. Follansbee
Keyword(s):  
Strain Rate ◽  
Applied Stress ◽  
Threshold Stress ◽  
Rate Sensitivity ◽  
Viscous Drag ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Threshold Strength ◽  
Mechanism Transition ◽  
Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

Sign in / Sign up

Export Citation Format

Share Document