Investigation into the micro deep drawing capabilities of a specially engineered refined aluminium alloy

During miniaturisation, size of the part comes close to grain size of the material. There is an overall decrease in the total number grains undergoing deformation and most of these are surface grains. Therefore, microscale deformation is marked by abnormal stress-strain response which limits the manufacturing capabilities of microforming. Two distinct phenomena responsible for this are: (i) dominance of single crystal deformation behaviour, and (ii) increased strain localisation due to incompatibly between surface and core grains during deformation. The present work attempts to neutralise these effects by increasing the number of grains in the deformation zone. This has been achieved by engineering refined microstructure in the materials. To develop the refined microstructure, cryorolling followed by controlled annealing treatment has been employed. Microscale deformation behaviour and microforming capabilities of the refined material have been compared with its coarse-grained counterpart by analysing their tensile curves and by post-mortem study of micro deep drawn components over a wide range of sample thicknesses. Material with fully recrystallised, equiaxed, strain-free refined microstructure is found to have the best strain hardening response both in micro and macro deformation domains. This property is also reflected in the micro deep drawing capabilities of the same material.

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Microstructure Engineering of Commercially Pure Ni Sheets to Enhance Micro-Deep Drawing Formability

Volume 2: Materials; Biomanufacturing; Properties, Applications and Systems; Sustainable Manufacturing ◽

10.1115/msec2016-8609 ◽

2016 ◽

Author(s):

Marzyeh Moradi ◽

M. Ravi Shankar

Keyword(s):

Deep Drawing ◽

Orientation Imaging Microscopy ◽

Image Correlation ◽

Coarse Grained ◽

In Situ Observation ◽

Orientation Imaging ◽

Micro Deep Drawing ◽

Commercially Pure ◽

Deformation Mechanics ◽

Set Up

Effects of starting microstructure on deformation behavior of commercially pure Ni blanks during micro-deep drawing was studied utilizing microforming set up that sits inside the chamber of Scanning Electron Microscopy (SEM) enables in situ observation of material flow during deformation. Various microstructure fields were created in Ni blanks using Severe Plastic Deformation (SPD) and heat treatment. SEM based Digital Image correlation (DIC) technique was used to characterize the micromechanics of deformation and its relation to process outcomes/performance. Pre and post–deformation microstructure analysis was carried out by performing Orientation Imaging Microscopy (OIM) to track the microstructure evolution across the micro-formed blanks during deformation in order to identify the process anomalies originated from the characteristics of starting microstructure and its interaction with deformation mechanics. We showed that microstructurally graded sheets consisting of nano-grained/coarse-grained layers significantly improves the formability of micro-blanks and effectively delays strain localization and onset of instability/failure during micro-deep drawing.

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Hot Deformation Behaviour of Mn–Cr–Mo Low-Alloy Steel in Various Phase Regions

Metals ◽

10.3390/met10091255 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1255 ◽

Cited By ~ 1

Author(s):

Ivo Schindler ◽

Petr Opěla ◽

Petr Kawulok ◽

Jaroslav Sojka ◽

Kateřina Konečná ◽

...

Keyword(s):

Flow Stress ◽

Strain Rate ◽

Hot Deformation ◽

Deformation Behaviour ◽

True Strain ◽

Coarse Grained ◽

Peak Strain ◽

Compression Tests ◽

Wide Range ◽

Hot Deformation Behaviour

The deformation behaviour of a coarse-grained as-cast medium-carbon steel, alloyed with 1.2% Mn, 0.8% Cr and 0.2% Mo, was studied by uniaxial compression tests for the strain rates of 0.02 s−1–20 s−1 in the unusually wide range of temperatures (650–1280 °C), i.e., in various phase regions including the region with predominant bainite content (up to the temperature of 757 °C). At temperatures above 820 °C, the structure was fully austenitic. The hot deformation activation energies of 648 kJ·mol−1 and 364 kJ·mol−1 have been calculated for the temperatures ≤770 °C and ≥770 °C, respectively. This corresponds to the significant increase of flow stress in the low-temperature bainitic region. Unique information on the hot deformation behaviour of bainite was obtained. The shape of the stress-strain curves was influenced by the dynamic recrystallization of ferrite or austenite. Dynamically recrystallized austenitic grains were strongly coarsened with decreasing strain rate and growing temperature. For the austenitic region, the relationship between the peak strain and the Zener–Hollomon parameter has been derived, and the phenomenological constitutive model describing the flow stress depending on temperature, true strain rate and true strain was developed. The model can be used to predict the forming forces in the seamless tubes production of the given steel.

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Optimization of strength, ductility and wear resistance of low-carbon grade A shipbuilding steel by post-ECAP annealing

Metallurgical Research & Technology ◽

10.1051/metal/2021021 ◽

2021 ◽

Vol 118 (2) ◽

pp. 217

Author(s):

M. Demirtas ◽

D.M. Sekban

Keyword(s):

Wear Resistance ◽

Annealing Treatment ◽

High Hardness ◽

Coarse Grained ◽

Low Carbon ◽

Initial Sample ◽

Shipbuilding Steel ◽

Factors Affecting ◽

Angular Pressing ◽

Refined Microstructure

Effect of equal channel angular pressing (ECAP) and subsequent annealing on the microstructure, mechanical properties and tribological behavior of grade A shipbuilding steel was investigated. Coarse-grained microstructure of initial sample is eliminated during the ECAP at 375 °C and more refined microstructure is achieved. Post-ECAP annealing at 575 °C results in some grain growth, and also the cementite lamellae in the pearlite colonies is broken and got spheroidised during the annealing treatment. ECAP increases strength and hardness of steel significantly while it decreases the ductility. On the other hand, post-ECAP annealing treatment brings about an increase in ductility and diminishes the hardness, as expected. Strain hardening capacity, ductility, hardness and oxidation rate were found to be the main factors affecting wear resistance of the grade A steel. It was found that high hardness and strength, good wear resistance with sufficiently high ductility can be achieved in the grade A steel by applying ECAP + annealing processes.

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Patterns in diversity and composition of the microbenthos of subarctic intertidal beaches with different morphodynamics

Marine Ecology Progress Series ◽

10.3354/meps13419 ◽

2020 ◽

Vol 648 ◽

pp. 19-38

Author(s):

AI Azovsky ◽

YA Mazei ◽

MA Saburova ◽

PV Sapozhnikov

Keyword(s):

Species Abundance ◽

Abundance Ratio ◽

Wave Action ◽

Coarse Grained ◽

Sediment Properties ◽

Β Diversity ◽

Α Diversity ◽

Wide Range ◽

Similar Mode ◽

Abundance And Diversity

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

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Predictive modelling of soils’ hydraulic conductivity using artificial neural network and multiple linear regression

SN Applied Sciences ◽

10.1007/s42452-020-03974-7 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Charles Gbenga Williams ◽

Oluwapelumi O. Ojuri

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Hydraulic Conductivity ◽

Linear Regression ◽

Multiple Linear Regression ◽

Coarse Grained ◽

Soil Types ◽

Wide Range ◽

Artificial Neural ◽

Input Variables

AbstractAs a result of heterogeneity nature of soils and variation in its hydraulic conductivity over several orders of magnitude for various soil types from fine-grained to coarse-grained soils, predictive methods to estimate hydraulic conductivity of soils from properties considered more easily obtainable have now been given an appropriate consideration. This study evaluates the performance of artificial neural network (ANN) being one of the popular computational intelligence techniques in predicting hydraulic conductivity of wide range of soil types and compared with the traditional multiple linear regression (MLR). ANN and MLR models were developed using six input variables. Results revealed that only three input variables were statistically significant in MLR model development. Performance evaluations of the developed models using determination coefficient and mean square error show that the prediction capability of ANN is far better than MLR. In addition, comparative study with available existing models shows that the developed ANN and MLR in this study performed relatively better.

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Quantum information probes of charge fractionalization in large-N gauge theories

Journal of High Energy Physics ◽

10.1007/jhep05(2021)149 ◽

2021 ◽

Vol 2021 (5) ◽

Author(s):

Brandon S. DiNunno ◽

Niko Jokela ◽

Juan F. Pedraza ◽

Arttu Pönni

Keyword(s):

Degrees Of Freedom ◽

Gauge Theories ◽

Entanglement Entropy ◽

Coarse Grained ◽

Strongly Coupled ◽

Information Theoretic ◽

Large N ◽

Wide Range ◽

Charge Fractionalization ◽

Electric Flux

Abstract We study in detail various information theoretic quantities with the intent of distinguishing between different charged sectors in fractionalized states of large-N gauge theories. For concreteness, we focus on a simple holographic (2 + 1)-dimensional strongly coupled electron fluid whose charged states organize themselves into fractionalized and coherent patterns at sufficiently low temperatures. However, we expect that our results are quite generic and applicable to a wide range of systems, including non-holographic. The probes we consider include the entanglement entropy, mutual information, entanglement of purification and the butterfly velocity. The latter turns out to be particularly useful, given the universal connection between momentum and charge diffusion in the vicinity of a black hole horizon. The RT surfaces used to compute the above quantities, though, are largely insensitive to the electric flux in the bulk. To address this deficiency, we propose a generalized entanglement functional that is motivated through the Iyer-Wald formalism, applied to a gravity theory coupled to a U(1) gauge field. We argue that this functional gives rise to a coarse grained measure of entanglement in the boundary theory which is obtained by tracing over (part) of the fractionalized and cohesive charge degrees of freedom. Based on the above, we construct a candidate for an entropic c-function that accounts for the existence of bulk charges. We explore some of its general properties and their significance, and discuss how it can be used to efficiently account for charged degrees of freedom across different energy scales.

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Experimental Investigation on Micro Deep Drawing of Stainless Steel Foils with Different Microstructural Characteristics

Chinese Journal of Mechanical Engineering ◽

10.1186/s10033-021-00556-5 ◽

2021 ◽

Vol 34 (1) ◽

Author(s):

Jingwei Zhao ◽

Tao Wang ◽

Fanghui Jia ◽

Zhou Li ◽

Cunlong Zhou ◽

...

Keyword(s):

Stainless Steel ◽

Deep Drawing ◽

Annealing Temperature ◽

Localized Deformation ◽

Microstructural Characteristics ◽

Height Profile ◽

Annealing Temperatures ◽

Micro Deep Drawing ◽

Profile Distribution

AbstractIn the present work, austenitic stainless steel (ASS) 304 foils with a thickness of 50 µm were first annealed at temperatures ranging from 700 to 1100 ℃ for 1 h to obtain different microstructural characteristics. Then the effects of microstructural characteristics on the formability of ASS 304 foils and the quality of drawn cups using micro deep drawing (MDD) were studied, and the mechanism involved was discussed. The results show that the as-received ASS 304 foil has a poor formability and cannot be used to form a cup using MDD. Serious wrinkling problem occurs on the drawn cup, and the height profile distribution on the mouth and the symmetry of the drawn cup is quite non-uniform when the annealing temperature is 700 ℃. At annealing temperatures of 900 and 950 ℃, the drawn cups are both characterized with very few wrinkles, and the distribution of height profile, symmetry and mouth thickness are uniform on the mouths of the drawn cups. The wrinkling becomes increasingly significant with a further increase of annealing temperature from 950 to 1100 ℃. The optimal annealing temperatures obtained in this study are 900 and 950 ℃ for reducing the generation of wrinkling, and therefore improving the quality of drawn cups. With non-optimized microstructure, the distribution of the compressive stress in the circumferential direction of the drawn foils becomes inhomogeneous, which is thought to be the cause of the occurrence of localized deformation till wrinkling during MDD.

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Effect of Equal Channel Angular Pressing and Annealing on Corrosion Resistance of Al-Cu Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.803.226 ◽

2013 ◽

Vol 803 ◽

pp. 226-229

Author(s):

Da Ran Fang ◽

Chun Liu ◽

Feng Fang Liu

Keyword(s):

Corrosion Resistance ◽

Low Temperature ◽

Equal Channel Angular Pressing ◽

Annealing Treatment ◽

Coarse Grained ◽

Nacl Solution ◽

Angular Pressing ◽

Cu Alloy ◽

Low Temperature Annealing ◽

Ultrafine Grained

Al-3.9wt.%Cu alloy was subjected to equal channel angular pressing (ECAP) and subsequent low temperature annealing treatment, and the corrosion resistance of the samples was investigated by potentiodynamic polarization measurements in 3.5% NaCl solution. The results show that the corrosion rate of the ultrafine-grained alloy increases, in comparison with the coarse-grained alloy. Meanwhile, it is noted that the corrosion resistance of the alloy subjected to ECAP can be improved by relief annealing.

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Gelation Impairs Phase Separation and Small Molecule Migration in Polymer Mixtures

Polymers ◽

10.3390/polym12071576 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1576

Author(s):

Biswaroop Mukherjee ◽

Buddhapriya Chakrabarti

Keyword(s):

Phase Separation ◽

Rational Design ◽

Surface Segregation ◽

Multiscale Methods ◽

Coarse Grained ◽

Polymer Gel ◽

Polymer Mixtures ◽

Separation Processes ◽

Surface Migration ◽

Wide Range

Surface segregation of the low molecular weight component of a polymeric mixture is a ubiquitous phenomenon that leads to degradation of industrial formulations. We report a simultaneous phase separation and surface migration phenomena in oligomer–polymer ( O P ) and oligomer–gel ( O G ) systems following a temperature quench that induces demixing of components. We compute equilibrium and time varying migrant (oligomer) density profiles and wetting layer thickness in these systems using coarse grained molecular dynamics (CGMD) and mesoscale hydrodynamics (MH) simulations. Such multiscale methods quantitatively describe the phenomena over a wide range of length and time scales. We show that surface migration in gel–oligomer systems is significantly reduced on account of network elasticity. Furthermore, the phase separation processes are significantly slowed in gels leading to the modification of the well known Lifshitz–Slyozov–Wagner (LSW) law ℓ ( τ ) ∼ τ 1 / 3 . Our work allows for rational design of polymer/gel–oligomer mixtures with predictable surface segregation characteristics that can be compared against experiments.

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