The Effect of Slow-Constant Strain Rates on the Tensile Properties of Selected Alloys at Room and Elevated Temperatures

1974 ◽  
Vol 96 (2) ◽  
pp. 115-122 ◽  
Author(s):  
C. L. Dotson
Keyword(s):  
Strain Rate ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Strength Properties ◽  
Strain Rate Range ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Lower Strain ◽  
Temperature Ranges ◽  
Design Stress

Tensile tests were performed at constant strain rates from 10−2 to 10−5 min−1 on 5454-O and 1100-O aluminum alloys, A515 Grade 70 steel and B166 nickel alloy at room temperature and at elevated-temperature ranges where the design stress basis normally changes from tensile to creep-rupture controlled. The results in general showed that the strength of the alloys decreased at lower strain rates, and the sensitivity to strain rate was greater at elevated temperatures except where metallurgical phenomena such as dynamic strain aging negate the effects of strain rate. At the highest temperature the decrease in strength properties ranged from 11 to 50 percent over the strain rate range for different alloys.

Investigation of Dynamic Strain Ageing Effects of Low Alloy Steels 15Kh2MFA and 15Kh2NMFA

2005 ◽  
Vol 482 ◽  
pp. 367-370
Author(s):  
Miroslava Ernestová
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Low Alloy Steels ◽  
Strain Rates ◽  
Dynamic Strain Ageing ◽  
Strain Ageing ◽  
Lower Strain ◽  
Wide Range ◽  
Alloy Steels

The paper summarizes results of tensile tests in low alloy steel (LAS) specimens (steels 15Kh2MFA and 15Kh2NMFA). Slow Strain Rate Tensile tests (SSRT) were performed in air at temperatures from 22 to 325°C over a wide range of strain rates from 2.5×10-6 to 1.67×10-3 s-1. The possible effect of strain rate and temperature to mechanical properties of tested LAS is searched for. The dynamic strain ageing (DSA) was observed within certain temperature ranges at lower strain rates tested and its hardening effect in terms of the maximum strengthening stress decreased linearly with the increase of log strain rate. It has been found that the occurrence of susceptibility to environmentally assisted cracking (EAC) of tested steels in high temperature water (HTW) is corelated to the DSA behavior. The result suggest that DSA reduces ductility of reactor pressure vessel (RPV) steel and its role in enhancing the EAC of RPV steels should not be neglected, in view of the coincidence with susceptibility zones for DSA and EAC in terms of strain rate and temperature. A reasonable coincidence was observed between the susceptibility to DSA exhibited by SSRT in air and with the EAC behavior observed in laboratory experiments.

Effects of Strain Rate on Dynamic Strain Aging of SA508-III Steel

2014 ◽  
Vol 788 ◽  
pp. 334-339 ◽  
Author(s):  
Dan Yuan ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Jia Hua Liu
Keyword(s):  
Strain Rate ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Cell Structure ◽  
Tensile Tests ◽  
Dislocation Cell ◽  
Strain Rate Range ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Reduction Of Area

The dynamic strain aging (DSA) behavior of SA508-III steel was evaluated through tensile tests with different strain rates from 10-4 to 10-1s-1 at 350°C. The OM, SEM and TEM were carried out to observe the microstructures and fracture morphologies of the steel. The results show that the serrated flows appear in the stress-strain curves when the strain rate is between 10-3~10-2s-1, indicating that DSA occurs. Under the strain rate range, the tensile strength increases and the elongation and the reduction of area decrease. However, the fracture surface of the steel after tensile tests is still ductile. DSA in SA508-III steel at the strain rates from10-3 to 10-2s-1 is mainly caused by the interaction between the internal solute atoms and dislocations, which leads to the dislocations multiplication and the formation of sub-grain boundaries and dislocation cell structure.

scholarly journals Behavior of Dynamic Strain Aging in Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr Alloy Strip

2021 ◽  
Vol 59 (1) ◽  
pp. 8-13
Author(s):  
Il-Hyun Kim ◽  
Myung-Ho Lee ◽  
Yang-Il Jung ◽  
Hyun-Gil Kim ◽  
Jae-Il Jang
Keyword(s):  
Tensile Test ◽  
Strain Rate ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Rolling Direction ◽  
Rate Sensitivity ◽  
Dynamic Strain ◽  
Alloy Strip ◽  
Lower Strain ◽  
Temperature Ranges

The behavior of dynamic strain aging (DSA) in a Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr alloy strip was investigated at temperature ranges of 25–600 °C via a tensile test. The tensile test was performed at two different strain rates 8.33 × 10<sup>-5</sup> and 1.67 × 10<sup>-2</sup> s<sup>-1</sup>. The shear stress of the alloy strip revealed a linear dependency on the test temperature when the specimens were tested under a higher strain rate (1.67 × 10<sup>-2</sup> s<sup>-1</sup>). However, the linear relationship was broken due to DSA when the samples were deformed under a lower strain rate (8.33 × 10<sup>-5</sup> s<sup>-1</sup>). The discrepancy was most significant at 400 °C. The trend in DSA behavior was similar irrespective of the orientation of the samples, i.e., rolling direction (RD) or transverse direction (TD). However, the effect of DSA was larger in the TD samples than the RD samples. The phenomena were interpreted to the variation in work hardening exponents and strain rate sensitivity. The value of the exponent decreased from 0.14 to 0.08 along a RD and from 0.1 to 0.07 along a TD, respectively. However, the smallest value was observed at 400–500 °C irrespective of the specimen orientation, which is consistent with the DSA behavior. It is suggested that the DSA was caused by an interaction of moving dislocations with solute atoms typically oxygen.

Tensile Stress-Strain Curves Modeling of Four Kinds of Solders with Temperature and Rate Dependence

2005 ◽  
Vol 297-300 ◽  
pp. 905-911 ◽  
Author(s):  
Xu Chen ◽  
Li Zhang ◽  
Masao Sakane ◽  
Haruo Nose
Keyword(s):  
Tensile Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Rate Dependence ◽  
Strain Rates ◽  
Stress Strain ◽  
Rate Range

A series of tensile tests at constant strain rate were conducted on tin-lead based solders with different Sn content under wide ranges of temperatures and strain rates. It was shown that the stress-strain relationships had strong temperature- and strain rate- dependence. The parameters of Anand model for four solders were determined. The four solders were 60Sn-40Pb, 40Sn-60Pb, 10Sn-90Pb and 5Sn-95Pb. Anand constitutive model was employed to simulate the stress-strain behaviors of the solders for the temperature range from 313K to 398K and the strain rate range from 0.001%sP -1 P to 2%sP -1 P. The results showed that Anand model can adequately predict the rate- and temperature- related constitutive behaviors at all test temperatures and strain rates.

Dynamic Strain Ageing in a Twin-Induced Plasticity Steel

2013 ◽  
Vol 750 ◽  
pp. 88-91 ◽  
Author(s):  
Jiang Ying Meng ◽  
Li He Qian ◽  
Peng Cheng Guo ◽  
Fu Cheng Zhang
Keyword(s):  
Strain Rate ◽  
Critical Strain ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Dynamic Strain Ageing ◽  
Serrated Flow ◽  
Strain Behavior ◽  
Rate Region ◽  
Lower Strain ◽  
Twip Steels

This work was to clarify the characteristics of serrated flow in an austenitic FeMnC twin-induced plasticity (TWIP) steel at room temperature (RT) using both strain- and crosshead displacement-controlled tensile tests. Three types of serrations were observed in strain-controlled but not in displacement-controlled tests, indicating that strain-controlled tensile tests provide more deformation details. The occurrence of the different types of serrations depends on both strain rate and strain level. Type C serrations were observed in TWIP steels at RT for the first time. The critical strain for the onset of serrations exhibits a positive strain rate dependence at higher strain rates, whereas an “inverse” critical strain behavior was observed in the lower strain rate region.

Mechanical Behaviors of Alloy 617 with Varied Strain Rates at High Temperatures

2014 ◽  
Vol 783-786 ◽  
pp. 1182-1187
Author(s):  
Mattias Calmunger ◽  
Guo Cai Chai ◽  
Sten Johansson ◽  
Johan Moverare
Keyword(s):  
Strain Rate ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Fracture Strain ◽  
Tensile Tests ◽  
Strain Rates ◽  
Mechanical Behaviors ◽  
Contrast Imaging ◽  
Alloy 617 ◽  
Nickel Base

Nickel base alloys due to their high performances have been widely used in biomass and coal fired power plants. They can undertake plastic deformation with different strain rates such as those typically seen during creep and fatigue at elevated temperatures. In this study, the mechanical behaviors of Alloy 617 with strain rates from 10-2/s down to 10-6/s at temperatures of 650°C and 700°C have been studied using tensile tests. Furthermore, the microstructures have been investigated using electron backscatter detection and electron channeling contrast imaging. At relatively high strain rate, the alloy shows higher fracture strains at these temperatures. The microstructure investigation shows that it is caused by twinning induced plasticity due to DSA. The fracture strain reaches the highest value at a strain rate of 10-4/s and then it decreases dramatically. At strain rate of 10-6/s, the fracture strain at high temperature is now smaller than that at room temperature, and the strength also decreases with further decreasing strain rate. Dynamic recrystallization can also be observed usually combined with crack initiation and propagation. This is a new type of observation and the mechanisms involved are discussed.

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.

Tensile Properties of Hot Extruded Mg-Zn-Nd-Y-Zr Alloy at Elevated Temperatures

2011 ◽  
Vol 415-417 ◽  
pp. 1157-1163
Author(s):  
Xiao Zhou ◽  
Hai Tao Zhou ◽  
Zhen Dong Zhang ◽  
Rui Rui Liu ◽  
Li Bin Liu
Keyword(s):  
Strain Rate ◽  
Elevated Temperatures ◽  
Peak Stress ◽  
Tensile Tests ◽  
Grain Boundary Sliding ◽  
Strain Rates ◽  
Zk60 Alloy ◽  
Boundary Sliding ◽  
Increasing Temperature ◽  
Zr Alloy

Mechanical properties of extruded Mg-Zn-Nd-Y-Zr alloy are investigated by tensile tests at various temperatures range from room temperature to 350°C with strain rates of 6.0×10-4-6.0×10-1s-1. It is found that the peak decrease with increasing temperature and decreasing strain rate, while the elongation increases with increasing temperature and decreasing strain rate. When deformation temperature is over 250°C, superplasticity occurs. This is ascribed to grain boundary sliding accommodated cavities growth. . At low temperature, the peak stress are a relatively higher than that of ZK60 alloy. This is explained by the grain refining effect and the precipitates of Mg9Nd and Mg6Zn3Y2.

DYNAMIC TENSILE AND COMPRESSIVE STRESS-STRAIN CHARACTERISTICS OF MAGNESIUM ALLOYS AT ELEVATED TEMPERATURES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1135-1140 ◽  
Author(s):  
TEPPEI ARAMOTO ◽  
HIROSHI TACHIYA ◽  
AKIYOSHI HORI ◽  
AKIHIRO HOJO ◽  
YUSUKE MIYAZAKI
Keyword(s):  
Strain Rate ◽  
Magnesium Alloys ◽  
Dynamic Stress ◽  
Elevated Temperatures ◽  
Compressive Load ◽  
Tensile Load ◽  
Strain Rate Range ◽  
Stress Strain ◽  
Rate Range ◽  
Temperature Ranges

The dynamic stress-strain characteristics of magnesium alloys have not been clarified sufficiently. Thus, the study investigated both the compressive and tensile dynamic stress-strain characteristics of representative magnesium alloys: AZ61A-F, ZK60A-T5 and AZ31B-F at wide strain rate and temperature ranges. About the strain rate dependency, the dynamic stresses are higher than the static ones under both compressive and tensile loads at elevated temperatures; however the dynamic stress-strain relations change slightly in the dynamic strain rate range. Thus, the magnesium alloys has little strain rate dependence. However, the elongation of the dynamic stress-strain relations under tensile load tends to be larger than that of static one. About the temperature dependency, the yield and flow stresses of the investigated magnesium alloys under compressive load decrease abruptly at temperatures higher than about 600 K in the wide strain rate range. Meanwhile, the ones under tensile load decrease with the temperature more gently. Totally, the magnesium alloys exhibit low temperature dependence. Furthermore, as well known, the yield stresses caused under the tensile load exhibit about twice as high as those under compressive load. This study verified that such a characteristic can be observed over a wide strain rate and temperature ranges.

Research on Superplasticity of Supplied 5A06 Aluminium Alloy Sheet

2016 ◽  
Vol 838-839 ◽  
pp. 127-131
Author(s):  
Bao Peng Bi ◽  
Yong Wang
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Grain Boundary Sliding ◽  
Strain Rate Range ◽  
Alloy Sheet ◽  
Uniaxial Tensile ◽  
5A06 Aluminum Alloy ◽  
Bulging Test

Superplasticity of supplied 5A06 aluminum alloy is reviewed in this paper. Supplied 5A06 aluminum alloy is researched on superplasticity by the methods of same strain rate high temperature uniaxial tensile tests at temperature range375°C-500°Cand strain rate range 2.5×10-4s-1~1.0×10-2s-1. Microstructure and fracture of tensile samples are analyzed and discussed, deduce that grain boundary sliding (GBS) is the predominant deformation mechanism. Superplastic formability of the alloy is evaluated by gas bulging test at elevated temperatures. Gas bulging test demonstrates the deformation process parameters for the best superplastic formability is 400°Cand 0.005s-1 ,suggesting good application prospect for this aluminum alloy.

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