Strain Rate Effect on Microstructure of Dynamically Compressed Magnesium Alloy AZ31B

2013 ◽  
Vol 535-536 ◽  
pp. 137-140 ◽  
Author(s):  
Iram Raza Ahmad ◽  
Muhammad Syfiqu ◽  
Xiao Jing ◽  
Dong W. Shu
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Fuel Consumption ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Microstructural Analysis ◽  
Strain Rate Effect ◽  
Strain Rates ◽  
Magnesium Alloy Az31b ◽  
Protective Structures

Lightweight materials have been in focus in recent times for their use in automobiles, planes and protective structures for numerous benefits ranging from reduction in fuel consumption and increased payload in vehicles to lighter and stronger protective structures. For efficient use of materials in applications where they are subjected to unusual higher sudden loads, it is necessary to understand their mechanical behaviour under such conditions.In present study, the effect of strain rate on deformation of magnesium alloy AZ31Bunder compression has been investigated. The alloy is subjected to various strain rates as 10-4s-1, 500s-1 and 2500s-1 and the microstructural analysis was performed to see the changes in the microstructure of the alloy and their effect on the mechanical response of the alloy is portrayed.

Energy Absorption at High Strain Rate of Magnesium Alloy AZ31B

2020 ◽  
Vol 12 (05) ◽  
Author(s):  
M. M. Mubasyir ◽  
◽  
M. F. Abdullah ◽  
K. Z. Ku Ahmad ◽  
R. N. R. Othman ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Energy Absorption ◽  
High Strain ◽  
Magnesium Alloy Az31b

Dynamic Deformation Behavior of As-Extruded Mg-Gd-Y Magnesium Alloy and the Microstructural Evolution

2011 ◽  
Vol 284-286 ◽  
pp. 1579-1583
Author(s):  
Ping Li Mao ◽  
Zheng Liu ◽  
Chang Yi Wang ◽  
Feng Wang
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Deformation ◽  
Strain Rates ◽  
Compression Axis ◽  
Deformation Localization ◽  
Dynamic Deformation Behavior

The dynamic deformation behavior of an as-extruded Mg-Gd-Y magnesium alloy was studied by using Split Hopkinson Pressure Bar (SHPB) apparatus under high strain rates of 102 s-1 to 103s-1 in the present work, in the mean while the microstructure evolution after deformation were inspected by OM and SEM. The results demonstrated that the material is not sensitive to the strain rate and with increasing the strain rate the yield stress of as-extruded Mg-Gd-Y magnesium alloy has a tendency of increasing. The microstructure observation results shown that several deformation localization areas with the width of 10mm formed in the strain rates of 465s-1 and 2140s-1 along the compression axis respectively, and the grain boundaries within the deformation localization area are parallel with each other and are perpendicular to the compression axis. While increasing the strain rate to 3767s-1 the deformation seems become uniform and all the grains are compressed flat in somewhat. The deformation mechanism of as-extruded Mg-Gd-Y magnesium alloy under high strain rate at room temperature was also discussed.

scholarly journals Strain rate effect on the mechanical response of duplex stainless steel

2018 ◽  
Author(s):  
A. A. H. Ameri ◽  
J. P. Escobedo-Diaz ◽  
Md. Z. Quadir ◽  
M. Ashraf ◽  
W. Hutchison
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
Mechanical Response ◽  
Strain Rate Effect ◽  
Rate Effect

Strain Rate Effect on Shear Behavior of Open-Graded Aggregates

2017 ◽  
Vol 2655 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Thomas Gebrenegus ◽  
Jennifer E. Nicks ◽  
Michael T. Adams
Keyword(s):  
Strain Rate ◽  
Axial Strain ◽  
Shear Behavior ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Strength Parameter ◽  
Strain Rates ◽  
Rate Dependency ◽  
Confining Stress ◽  
Dilation Angle

Despite their wide application as construction materials in various earthworks built by state and local transportation agencies, the role of physical and mechanical factors in the strength and deformation behavior of crushed, manufactured open-graded aggregates (OGAs) is not well studied. In this investigation, the strain rate dependency of strength–deformation behaviors of two commonly employed crushed aggregates with small (12.7 mm) and large (38.1 mm) sizes is investigated. A 150-mm diameter triaxial testing device was used to conduct a drained compression test at five strain rates, ranging from 0.000083%/s to 0.0083%/s. To evaluate the significance of confining stress and density on the effect of strain rates, the shear tests were conducted at 34 kPa and 207 kPa effective confining stress levels, with the samples compacted at loose (30%) and dense (95%) relative densities. The peak friction angle, maximum dilation angle, secant modulus, and axial strain at which the aggregates started to dilate were determined to evaluate the strain rate effect on the shear behavior of OGAs. The results demonstrate that within the imposed quasistatic strain rate ranges, only the dilation angle showed an increasing trend with the increase in strain rate, whereas other extracted strength parameters were less sensitive to strain rate for both OGAs tested. Hence, the selection of strain rates according to ASTM specifications is appropriate for conducting strength parameter tests, used by practitioners for the design of geotechnical structures, on OGAs under quasistatic conditions.

Hot working of SP-700 titanium alloy with lamellar α + β starting structure using a processing map

2020 ◽  
Vol 111 (4) ◽  
pp. 297-306
Author(s):  
Amir Hosein Sheikhali ◽  
Maryam Morakkabati
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Microstructural Analysis ◽  
Shear Bands ◽  
Alpha Phase ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range

Abstract In this study, hot deformation behavior of SP-700 titanium alloy was investigated by hot compression tests in the temperature range of 700-9508C and at strain rates of 0.001, 0.1, and 1 s-1. Final mechanical properties of the alloy (hot compressed at different strain rates and temperatures) were investigated using a shear punch testing method at room temperature. The flow curves of the alloy indicated that the yield point phenomenon occurs in the temperature range of 800- 9508C and strain rates of 0.1 and 1 s-1. The microstructural analysis showed that dynamic globularization of the lamellar α phase starts at 7008C and completes at 8008C. The alpha phase was completely eliminated from b matrix due to deformation- induced transformation at 8508C. The microstructure of specimens compressed at 8508C and strain rates of 0.001 and 0.1 s-1showed the serration of beta grain boundaries, whereas partial dynamic recrystallization caused a necklace structure by increasing strain rate up to 1 s-1. The specimen deformed at 7008C and strain rate of 1 s-1was located in the instability region and localized shear bands formed due to the low thermal conductivity of the alloy. The processing map of the alloy exhibited a peak efficiency domain of 54% in the temperature range of 780-8108C and strain rates of 0.001- 0.008 s-1. The hot deformation activation energy of the alloy in the α/β region (305.5 kJ mol-1) was higher than that in the single-phase β region (165.2 kJ mol-1) due to the dynamic globularization of the lamellar a phase.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8to 3.1 × 10–4ms–1and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5s–1, the maximum strength increased with decreasing strain-rate but below 10–5s–1it decreased with decreasing strain-rate.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8 to 3.1 × 10–4 ms–1 and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5 s –1, the maximum strength increased with decreasing strain-rate but below 10–5 s–1 it decreased with decreasing strain-rate.

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 Anisotropic mechanical behaviour of calendered nonwoven fabrics: Strain-rate dependency

2020 ◽  
pp. 002199832097679
Author(s):  
V Cucumazzo ◽  
E Demirci ◽  
B Pourdeyhimi ◽  
VV Silberschmidt
Keyword(s):  
Strain Rate ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Elastic Response ◽  
Uniaxial Tensile ◽  
Rate Dependency ◽  
Fibrous Matrix ◽  
Nonwoven Fabrics ◽  
Linear Elastic

Calendered nonwovens, formed by polymeric fibres, are three-phase heterogeneous materials, comprising a fibrous matrix, bond-areas and interface regions. As a result, two main factors of anisotropy can be identified. The first one is ascribable to a random fibrous microstructure, with the second one related to orientation of a bond pattern. This paper focuses on the first type of anisotropy in thin and thick nonwovens under uniaxial tensile loading. Individual and combined effects of anisotropy and strain rate were studied by conducting uniaxial tensile tests in various loading directions (0°, 30°, 45°, 60° and 90° with regard to the main fabric’s direction) and strain rate (0.01, 0.1 and 0.5 s−1). Fabrics exhibited an initial linear elastic response, followed by nonlinear strain hardening up to necking and final softening. The studied allowed assessment of the extent the effects of loading direction (anisotropy), planar density and strain rate on the mechanical response of the calendered fabrics. The evidence supported the conclusion that anisotropy is the most crucial factor, also delineating the balance between the fabric’s load-bearing capacity and extension level along various directions. The strain rate produced a marked effect on the fibre’s response, with increased stress at higher strain rate while this effect in the fabric was small. The results demonstrated the differences of the mechanical behaviour of fabrics from that of their constituent fibres.

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