Strength of Steel in a Lower Strain Rate Range (Study on the Dependence of Mechanical Properties of Metals upon the Strain Rate, 7th Report)

The results of experimental study of mechanical properties of samples of lime-sand brick under dynamic loading are presented. The tests were carried out using the traditional Kolsky method and its modification - dynamic splitting (the so-called «Brazilian test»). The laws of change in strength, strain, time properties and energy intensity of the investigated material are established in the strain rate range of 5·102-2.5·103 s-1 under compression and in the stress rate range of 2·101-3·102 GPa/s under tension.

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Influence of Mg Content, Grain Size and Strain Rate on Mechanical Properties and DSA Behavior of Al-Mg Alloys Processed by ECAP and Annealing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.794-796.870 ◽

2014 ◽

Vol 794-796 ◽

pp. 870-875 ◽

Cited By ~ 3

Author(s):

Min Zha ◽

Yan Jun Li ◽

Ragnvald H. Mathiesen ◽

Christine Baumgart ◽

Hans J. Roven

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Strain Rate ◽

Room Temperature ◽

Uniform Elongation ◽

Mg Alloys ◽

Lower Strain Rate ◽

Lower Strain ◽

Mg Content ◽

Al Mg Alloys

Ultrafine-grained (UFG) binary Al-xMg (x=1, 5 and 7 wt %) alloys were processed by equal channel angular pressing (ECAP) at room temperature via route Bccombined with inter-pass annealing. The effects of Mg content, grain size and strain rate on mechanical properties and dynamic strain aging (DSA) behaviour of the Al-Mg alloys upon tensile testing at room temperature were studied. An increase in Mg content from 5 to 7 wt % leads to a pronounced increase in strength and uniform elongation in both the as-homogenized and as-ECAP Al-Mg alloys. Thereby, the Al-7Mg alloy, either prior to or after ECAP processing, possess significantly higher strength and comparable or even higher uniform elongation than the more dilute Al-Mg alloys. However, the as-ECAP Al-Mg alloys exhibit significantly higher strength but little work hardening and hence rather limited uniform elongation. In general, decreasing grain size leads to significant increase in strength while dramatic decrease in ductility. Moreover, DSA serration amplitudes increase with reducing grain size in the micrometer range. However, the UFG Al-Mg alloys exhibit much less DSA effect than the micrometer scaled grain size counterparts, i.e. probably due to the high dislocation densities and special grain boundary features in the UFG materials. Also, the Al-Mg alloys, especially those with a UFG structure, exhibit higher strength and ductility at lower strain rate than at higher strain rate, due mainly to enhanced DSA effect and hence work hardening at a lower strain rate.

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Effect of Strain Rate on the Mechanical Properties of Cu/Ni Clad Foils

Materials ◽

10.3390/ma14226846 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6846

Author(s):

Haiyang Wang ◽

Chuanjie Wang ◽

Linfu Zhang ◽

Gang Chen ◽

Qiang Zhu ◽

...

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Rate Sensitivity ◽

Interface Layer ◽

Strain Rate Range ◽

Coarse Grained ◽

Uniaxial Tensile ◽

Rate Range ◽

Static Strain

The performance of clad foils in microforming deserves to be studied extensively, where the strain rate sensitivity of the clad foil concerning the forming performance is a crucial factor. In this paper, the strain rate sensitivity of the mechanical properties of coarse-grained (CG) Cu/Ni clad foils in the quasi-static strain rate range (ε˙=10−4 s−1~10−1 s−1) is explored by uniaxial tensile tests under different strain rates. The results show that the strength and ductility increase with strain rate, and the strain rate sensitivity m value is in the range of 0.012~0.015, which is three times the value of m for CG pure Cu. The fracture morphology shows that slip bands with different directions are entangled in localized areas near the interface layer. Molecular dynamics simulations demonstrate the formation of many edged dislocations at the Cu/Ni clad foils interface due to a mismatch interface. The improved ductility and strain rate sensitivity is attributed to the interaction and plugging of the edged dislocations with high density in the interface layer. Additionally, the influence of size effect on mechanical properties is consistently present in the quasi-static strain rate range. This paper helps to understand the strain rate sensitivity of CG clad foils and to develop clad foils in microforming processes.

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Experimental Study on the Influence of Freezing Pressure on the Uniaxial Mechanical Properties of Ice

Advances in Civil Engineering ◽

10.1155/2021/8651467 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Baosheng Wang ◽

Weihao Yang ◽

Peixin Sun ◽

Xin Huang ◽

Yaodan Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Residual Stress ◽

Strain Rate ◽

Uniaxial Compression ◽

Peak Stress ◽

Strain Rate Range ◽

Brittleness Index ◽

Rate Range ◽

Minimum Value ◽

Maximum Minimum

In this study, a test technique that enables continuous control of the sample stress state from freezing to testing is proposed to investigate the influence of freezing pressure on the mechanical properties of ice under uniaxial compression. In this method, the water is frozen into the standard cylindrical ice specimen under high hydraulic pressure in a triaxial pressure chamber, and then, the temperature field and stress field of the ice specimens are adjusted to the initial state of the test; finally, an in situ mechanical test is conducted in the triaxial chamber. The uniaxial compression test of ice specimens with temperature of −20°C and freezing pressure of 0.5–30 MPa is performed in the strain rate range of 5 × 10−5−1.5 × 10−6 s−1. The results show that, as the freezing pressure increases, the ductile-to-brittle transition zone of the ice specimen during failure moves to the low strain rate range, and the failure mode of the specimen changes from shear failure to splitting failure. Further, the brittleness index of the ice specimen first increases, then decreases, and then again increases with the increase in freezing pressure. The brittleness index reaches the maximum (minimum) when the freezing pressure is 30 MPa (20 MPa). The peak stress of the ice specimen also increases first, then decreases, and then increases with the increase in freezing pressure. The maximum value is also at the freezing pressure of 30 MPa, but the minimum value is obtained at the freezing pressure of 0.5 MPa. The failure strain of the ice specimen first decreases and then increases with the increase in freezing pressure, and the maximum (minimum) value is achieved at the freezing pressure of 0.5 MPa (10 MPa). When the ice specimen exhibits brittle failure, the relationships between the residual stress and the freezing pressure and between the peak stress and freezing pressure are the same, but when the ice specimen exhibits ductile failure, there is no obvious relationship between the residual stress and the freezing pressure.

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Behavior of Elastic Therapeutic Tapes under Dynamic and Static Conditions

Advances in Materials Science and Engineering ◽

10.1155/2021/6671712 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Hermela Ejegu ◽

Bipin Kumar ◽

Priyanka Gupta

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Internal Stress ◽

Dynamic Condition ◽

Physical And Mechanical Properties ◽

Static Condition ◽

Strain Rates ◽

Lower Strain Rate ◽

Lower Strain ◽

Static Conditions

The aim of this paper is to determine the relaxation behavior of the therapeutic tape under different thermomechanical conditions over different time spans and to analyze the physical and mechanical properties of selected kinesiology tapes. The relaxation test was conducted under a static condition with two extended levels (25% and 50%) for one hour and a dynamic condition for 300 cycles with different loading-unloading values, strain rates, and temperatures. For both static and dynamic conditions, at a lower strain rate and higher load and temperature, the therapeutic tapes showed higher loss of internal stress and faster losses of efficiency. Under all selected conditions, the tape’s stress has decreased rapidly.

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Experimental Study of In-plane Mechanical Properties of Carbon Fibre Woven Composite at Different Strain Rates

Polymers and Polymer Composites ◽

10.1177/096739111702500406 ◽

2017 ◽

Vol 25 (4) ◽

pp. 289-298 ◽

Cited By ~ 1

Author(s):

Jiahai Lu ◽

Ping Zhu ◽

Qinghui Ji ◽

Zhang Cheng

Keyword(s):

Mechanical Properties ◽

Carbon Fibre ◽

Strain Rate ◽

Complex Loading ◽

Axial Direction ◽

Strain Rate Range ◽

Strain Rates ◽

Woven Composite ◽

Rate Range ◽

Failure Patterns

Carbon fibre woven composite has been increasingly employed in engineering applications undergoing complex loading conditions. For effective use of composite material in dynamic applications, it is essential to fully understand the mechanical behaviour of composite at different strain rates. In the present study, both in-plane tensile and compressive experiments loaded at 0 degree axial direction and 45 degree off-axial direction of a TC33 carbon fibre woven composite were investigated over the strain rate range from 0.001 to 1000 s−1. High strain rate tests were carried out using Split Hopkinson Pressure and Tensile Bar apparatus respectively. The results indicated that the in-plane mechanical properties and failure patterns were strain rate sensitive under both tensile and compressive loadings. The mechanical properties, failure patterns and strain rate effect also showed highly direction dependent and tension/compression asymmetric characteristic within the considered strain rate range. For higher strain rate sensitivity under compression than that under tension, the asymmetry of mechanical properties was less obvious with the increase of strain rate. Finally, two phenomenal models were proposed to quantitatively fit the relationship between strength property and strain rate.

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Tensile Properties of MoSi2 at Elevated Temperatures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.449-452.845 ◽

2004 ◽

Vol 449-452 ◽

pp. 845-848 ◽

Cited By ~ 2

Author(s):

Ai Dang Shan ◽

Jian Sheng Wu ◽

Hitoshi Hashimoto ◽

Yong Ho Park

Keyword(s):

Activation Energy ◽

Grain Size ◽

Strain Rate ◽

Tensile Properties ◽

Elevated Temperatures ◽

Strain Rate Range ◽

Rate Range ◽

Energy Value ◽

Lower Strain ◽

Ductility Maximum

The tensile properties of two MoSi2 alloys with different grain sizes (1 micrometer and 10 micrometer) were evaluated in vacuum at temperatures ranging from 1400 to 1600K and initial strain rates ranging from 1×10-5/s to 1×10-3/s. For the alloy with 10micron grain size an m vale of 0.35 and an activation energy value of 350 kJ/mol were observed in the lower strain rate range while an m value of 0.12 and an activation energy value of 760 kJ/mol were observed in the higher strain rate range. For the alloy with 1micron grain size, a uniform m value of 0.55 and an activation energy value of 160 kJ/mol were observed. Moreover these two alloys showed remarkable ductility (maximum 33%) in the test temperatures. The deformation mechanism and the remarkable ductility are discussed in the light of the microstructural observations through SEM and TEM.

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OS13-2-1 How to determine mechanical properties in dynamic compression for light sheet metals in a wide strain-rate range up to 10^6 s^

The Abstracts of ATEM International Conference on Advanced Technology in Experimental Mechanics Asian Conference on Experimental Mechanics ◽

10.1299/jsmeatem.2007.6._os13-2-1- ◽

2007 ◽

Vol 2007.6 (0) ◽

pp. _OS13-2-1--_OS13-2-1-

Author(s):

Yasuhisa Sato ◽

Masatake Yoshida

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Dynamic Compression ◽

Light Sheet ◽

Strain Rate Range ◽

Sheet Metals ◽

Rate Range

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Dynamic Mechanical Behavior and Microstructure Evolution of an Extruded 6013-T4 Alloy at Elevated Temperatures

Metals ◽

10.3390/met9060629 ◽

2019 ◽

Vol 9 (6) ◽

pp. 629 ◽

Cited By ~ 2

Author(s):

Tuo Ye ◽

Yuanzhi Wu ◽

Wei Liu ◽

Bin Deng ◽

Anmin Liu ◽

...

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Stress Level ◽

Microstructure Evolution ◽

Elevated Temperatures ◽

Strain Rate Range ◽

Rate Range ◽

Dynamic Mechanical Behavior ◽

Strain And Strain Rate ◽

Increasing Temperature

The mechanical properties of an extruded 6013-T4 alloy were tested at a temperature range from 25 to 400 °C and strain rate range from 1 × 103 to 5 × 103 s−1. The results demonstrate that the stress level is sensitive to strain rate and temperature. The stress level increases slightly with increasing strain rate and decreases remarkably with increasing temperature. The dislocation and precipitate undergo great changes. When deformed at 25 °C, the density of the dislocation increases with strain and strain rate; which leads to a higher stress level. A great number of needle-like precipitates were observed at samples deformed at 200 °C. It is clear that the density of dislocation increases with strain and strain rate. When impacted at 400 °C, the coarser precipitates were found in the specimen; the density of the dislocation increases with strain and strain rate.

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Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽

10.3390/met9080880 ◽

2019 ◽

Vol 9 (8) ◽

pp. 880 ◽

Cited By ~ 2

Author(s):

Rongchuang Chen ◽

Haifeng Xiao ◽

Min Wang ◽

Jianjun Li

Keyword(s):

Flow Stress ◽

Strain Rate ◽

Hot Working ◽

Ex Situ ◽

Lower Strain Rate ◽

Hot Workability ◽

Compression Tests ◽

300M Steel ◽

Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

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