Showing papers on "Strain rate published in 2017"
13 Jan 2017-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the properties of AM-Selective Laser Melting (SLM) AlSi10Mg parts under a static regime have been investigated, while the strain rate sensitivity of these materials, to the best of our knowledge, has not been discussed in the literature.
Abstract: Implementation of Additive Manufacturing (AM) parts in the growing applications within the automotive and aerospace industries encourages further investigations of the material behavior under various strain rates, spanning from quasi-static to the high strain rate regimes. Although mechanical properties of AM-Selective Laser Melting (SLM) AlSi10Mg parts under a static regime have been investigated, the strain rate sensitivity of these materials, to the best of our knowledge, has not been discussed in the literature. In this work, the properties of AM-SLM AlSi10Mg material were systematically investigated under a wide range of strain rates, spanning from 2.77×10−6 to 2.77×10−1 S−1. The AM-SLM AlSi10Mg alloy, as opposed to Al alloys fabricated by conventional methods, was found to be strain rate sensitive with significant changes to the flow stress and strain hardening exponents with an increase in strain rate. The fracture mechanisms of these specimens, built in different orientations, are discussed.
156 citations
TL;DR: In this paper, a numerical model was developed to predict the damage behaviors of composite sandwich structures with a honeycomb core subjected to low-velocity perforation impact, addressing the intra-laminar damage, interlaminar and adhesive delamination and strain rate effect of the materials.
151 citations
TL;DR: In this paper, the authors investigated the effect of strain rate on hydrogen embrittlement behavior in a low-carbon martensitic steel and found that the deformation at a lower strain rate facilitated hydrogen to accumulate mainly on prior austenite grain boundaries.
133 citations
TL;DR: In this paper, an investigation was conducted to examine the mechanical behavior and microstructure evolution during deformation of ultrafine-grained pure magnesium at low temperatures within the temperature range of 296-373 K. Discs were processed by high pressure torsion until saturation in grain refinement.
131 citations
TL;DR: In this paper, the authors investigated the hot deformation behaviors of a nickel-based superalloy, and the hot compressive tests were conducted at the deformation temperature range of 920-1040°C and strain rate range of 0.001-1s−1.
128 citations
TL;DR: In this article, the effects of various strain rates on the fracture toughness as well as the energy-release rate of gas shales were investigated using three-point bending method was applied using notched semicircular bending shale specimens that were prepared as per the international standards.
126 citations
10 May 2017-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
Abstract: Here we introduce a novel thermo-mechanical Solid State Additive Manufacturing (SSAM) process referred to as Additive Friction Stir (AFS) manufacturing that provides a new and alternative path to fusion-based additive manufacturing processes for developing fully-dense, near-net shape components with a refined-equiaxed grain morphology. This study is the first to investigate the beneficial grain refinement and densification produced by AFS in IN625 that results in advantageous mechanical properties (YS, UTS, ef) at both quasi-static and high strain rate. Electron Backscatter Diffraction (EBSD) observed grain refinement during the layer deposition in the AFS specimens, where the results identified fine equiaxed grain structures with even finer grain structures forming at the layer interfaces. The EBSD quantified grains as fine as 0.27 µm in these interface regions while the average grain size was approximately 1 µm. Additionally, this is the first study to report on the strain rate dependence of AFS IN625 through quasi-static (QS) (0.001/s) and high strain rate (HR) (1500/s) tensile experiments using a servo hydraulic frame and a direct tension-Kolsky bar, respectively, which captured both yield and ultimate tensile strengths increasing as strain rate increased. The HS results exhibited an approximately 200 MPa increase in engineering strength over the QS results, with the fracture surfaces at both strain rates aligned with the maximum shear plane and exhibiting localized microvoids.
124 citations
TL;DR: In this paper, an experimental investigation into the dynamic compressive response of high-strength concrete with three different strengths (60, 80, and 110 MPa) was conducted using a Denison Universal Testing Machine and a Split Hopkinson Pressure Bar (SHPB) device, and the effects of strain rate on their mechanical properties were examined.
113 citations
TL;DR: In this paper, a series of uniaxial compressive tests were conducted on saturated frozen Helin loess under five different strain rates (1,×10 −-2 /s, 1,× 10 −-3 /s), 1, × 10 −−4 /s and 5 × 10−5 −5 /s).
113 citations
TL;DR: In this article, the uni-axial dynamic compressive behavior of recycled aggregate concrete (RAC) and RAC with carbonated coarse aggregate (CRAC) was experimentally investigated when the strain rates were between 10 −5 /s and 10 −1 /s.
113 citations
TL;DR: In this article, the plastic deformation characteristics (including the hardness, strain rate sensitivity, and activation volume) of nanocrystalline (NC) equiatomic NbMoTaW body-centered cubic (BCC) high-entropy alloy films (HEAFs) with thicknesses spanning from 100 to 2000nm at room temperature were investigated.
TL;DR: In this paper, the effect of strain rate on the mechanical response of ultra-high performance concrete (UHPC) in tension is investigated, and an analysis of the data presented therein is presented.
TL;DR: In this article, the authors identify plastic flow behavior and microstructural evolution during sub-transus hot deformation of a Ti-6Al-4V alloy with three initial microstructures through compressive deformation at different strain rates in a Gleeble simulator and via SEM and TEM examinations.
TL;DR: In this paper, the deformation behavior of a phosphorous-modified super austenitic stainless steel was studied in the temperature range of 1173-1423-K and strain rate range of 0.001-10−s−1 employing thermomechanical simulator.
TL;DR: In this paper, a constitutive equation was formulated for describing interdependency between deformation temperature, strain rate, flow stress and strain, and the estimated apparent activation energy (Q) ∼350 kJmol-1 for the hot deformation was approximately similar to the activation energy for diffusion of the slowest diffusing element Ni in this alloy.
TL;DR: In this article, the compressive behavior of Ti-6Al-4V lattice structures with rhombic dodecahedron unit cells is investigated at four different strain rates, and the peak stress exhibits a certain dependence on the loading rate for the structures with smaller unit cells.
TL;DR: In this paper, anisotropic mechanical properties were experimentally determined and compared for three types of commercially available Li-ion battery separators: Celgard 2325, Celgard PP2075 dry-processed polymer separators, and DreamWeaver Gold 40 non-woven separator.
TL;DR: In this paper, the mechanical response and texture evolution of rare-earth-containing magnesium alloy sheet, ZEK100, are measured under uniaxial (tension and compression) loading along the rolling direction (RD), 45° to rolling direction(DD), transverse direction (TD) and normal direction (ND), at the strain rate of 10 −4 to 3 ǫ 10 3 s −1, and temperatures of 22 Â c and 150 Â C.
TL;DR: In this paper, an anisotropic fracture criterion is proposed for ductile fracture of lightweight metals, which couples effect of stress triaxiality on void growth, and assumes the shear linking-up of voids governed by the largest shear stress.
TL;DR: In this paper, three different types of strainhardening, cement-based composites (SHCC) as well as their constitutive cementitious matrices were investigated under uniaxial quasi-static and impact tensile loading.
TL;DR: In this paper, the flow and fracture behavior of 7075-T651 aluminum alloy has been studied under different stress states, strain rate and temperature in order to explore the characteristics of the material under extreme situations developed in aerospace and armor structures.
17 Jul 2017-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the evolution of twins is quantified by measuring twin boundary length fraction and length density, and the twin length density increases with increase in DRX fraction at low temperatures.
Abstract: Dynamic recrystallization (DRX) kinetics and its association with annealing twins in alloy 617 has been studied in a range of strain rates (0.001 s −1 to 10 s −1 ) and temperatures (1173–1473 K). In both low ( −1 ) and high (≥ 1 s −1 ) strain rate domains, DRX fraction is high as compared to intermediate strain rate (~ 0.1 s −1 ). The lower critical strain for DRX initiation with higher growth of DRX grains is responsible for large DRX fraction with coarse grains microstructure in the low strain rate domain. In contrast, DRX at higher strain rates is mainly controlled by the large stored energy along with adiabatic temperature rise which leads to higher DRX nucleation. It is also noticed that the evolution of twins is greatly influenced by deformation temperature at all imposed strain rates. Here, the evolution of twins is quantified by measuring twin boundary length fraction and length density. The twin-length density increases with increase in DRX fraction at low temperatures (
TL;DR: In this article, the effects of high strain rate and elevated temperature on the deformation behaviors of FeCr alloy specimen, obtained by laser additive manufacturing (LAM), were investigated by Split Hopkinson Pressure Bar tests with the strain rates of 1000 −8000 s −1 and temperature range of 20 −800 ˚C.
TL;DR: In this article, the authors examined the ferrite softening mechanisms in the austenite/ferrite microstructure as a function of the strain rate at a high deformation temperature.
TL;DR: In this article, the effect of strain rate on the cyclic loading tests was investigated and the applicability of a constant life diagram (CLD) model to determine the fatigue limit of the alloy for different stress ratios (R).
TL;DR: In this article, the authors studied the hot deformation behavior of Ni3Al-based alloy and determined the activation deformation energy as 802.71 ǫkJ/mol.
08 Feb 2017-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a CoCrFeNiMn high-entropy alloy was processed by high-pressure torsion to produce a grain size of ~10nm and then tested in tension at elevated temperatures from 773 to 1073 K using strain rates in the range from 1.0×10−3 s−1.
Abstract: A CoCrFeNiMn high-entropy alloy was processed by high-pressure torsion to produce a grain size of ~10 nm and then tested in tension at elevated temperatures from 773 to 1073 K using strain rates in the range from 1.0×10−3 to 1.0×10−1 s−1. The alloy exhibited excellent ductility at these elevated temperatures including superplastic elongations with a maximum elongation of >600% at a testing temperature of 973 K. It is concluded that the formation of precipitates and the sluggish diffusion in the HEA inhibit grain growth and contribute to a reasonable stability of the fine-grained structure at elevated temperatures. The results show the activation energy for flow matches the anticipated value for grain boundary diffusion in nickel but the strain rate sensitivity is low due to the occurrence of some grain growth at these high testing temperatures.
TL;DR: In this paper, the authors used non-equilibrium molecular dynamics simulations to characterize the ductile tensile failure of a model body-centered cubic metal, tantalum, over six orders of magnitude in strain rate.
TL;DR: In this article, the deformation characteristics of high entropy alloy thin films (HEAFs) were investigated, and the detwinning softening process was combined with conventional strengthening mechanisms to elucidate the mechanical properties of AlxCoCrFeNi HEAFs.
TL;DR: In this article, a novel process methodology to concurrently improve the compressive strength (2078 MPa) at a strain rate of 5 × 10−4 s−1 and strain-to-failure (over 40%) of bulk tungsten materials has been described.