Investigations of size effect on formability and microstructure evolution in SS304 thin foils

2018 ◽  
Vol 53 (7) ◽  
pp. 517-528
Author(s):  
Jambeswar Sahu ◽  
Shanta Chakrabarty ◽  
Rajesh Raghavan ◽  
Sushil Mishra
Keyword(s):  
Microstructure Evolution ◽  
Mechanical Response ◽  
Deformation Behaviour ◽  
Sheet Material ◽  
Foil Thickness ◽  
Dome Height ◽  
Forming Process ◽  
Thin Foils ◽  
Grain Misorientation ◽  
The Impact

In the micro-forming process when the thickness of the sheet material is comparable to the intrinsic length scales of that material, deformation behaviour differs from that which is expected in the macroscopic sheet material. In this study, size effects of SS304 foils have been investigated using tensile and limiting dome height tests along with careful microstructural investigations. SS304 foils of differing thicknesses but similar grain size have been deformed under varying strain path conditions to capture the impact of foil thickness on the mechanical response and microstructure evolution. Formability curves for SS304 foils constructed from limiting dome height tests show that limit strains increase with increasing foil thickness. Microstructure investigations highlight the importance of grain misorientation, twin fraction and texture on the formability of SS304 foils.

scholarly journals Haptic input devices with intelligent signal processing ensuring process stability and quality management

2020 ◽  
Vol 3 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Alexander Graf ◽  
Ricardo Decker ◽  
René Schmidt ◽  
Verena Kräusel ◽  
Lothar Kroll ◽  
...  
Keyword(s):  
Continuous Production ◽  
Centre Console ◽  
Sensory Function ◽  
Foil Thickness ◽  
Special Focus ◽  
Forming Process ◽  
Sensor Layer ◽  
Input Devices ◽  
The Impact ◽  
Haptic Input

As part of the Cluster of Excellence Merge, a complete process chain was developed for the production of a hybrid laminate with sensory function for continuous production processes. An interior surface of the VW UP! is a good example of this. In this work, the forming processes of the centre console and the parameters influencing quality are discussed. An important parameter for the polarisation of the sensor layer is the thickness of the piezoceramic foil after forming. The maximum signal quality can only be achieved by an exact prediction of the thinning of the foil during the forming process. In addition, the electrical characterisation, especially the capacitance, of the sensor areas is used to determine the foil thickness within the sensor areas in the complex-shaped centre console. Furthermore, a practicable polarisation strategy is deducted in consideration of thickness, electrical characteristics of the piezoceramic foil and process parameters of forming process. For evaluation a novel impact localisation method based on machine learning is shown. Special focus is put on the independence of the impact intensity in order to guarantee a user-independent operation. In this respect, the suitability of various intensity-independent localisation methods will be discussed and subsequently empirically evaluated.

Structure Development and Deformation Behaviour of Pure Aluminium Processed by Constrained Groove Pressing

2014 ◽  
Vol 794-796 ◽  
pp. 882-887
Author(s):  
Jozef Zrník ◽  
Miroslav Cieslar ◽  
Peter Slama
Keyword(s):  
Tensile Strength ◽  
Deformation Behaviour ◽  
Electron Back Scatter Diffraction ◽  
Pure Aluminium ◽  
Deformation Method ◽  
Substantial Impact ◽  
Thin Foils ◽  
Commercial Purity Aluminium ◽  
Deformation Step ◽  
The Impact

In this study, the relationship between the structure and properties of commercial purity aluminium alloy A1199 was investigated by applying constrained groove pressing (CGP) deformation method. The refinement of the coarse grain aluminium (Al) microstructure to sub microcrystalline size by large plastic strain at room temperature defined. The impact of various strains upon microstructure changes is investigated using transmission electron microscopy (TEM of thin foils) and electron back scatter diffraction (EBSD). A mixture of subgrains produced by grains subdivision and polygonized subgrains formed locally due to dynamic recovery was found in the deformed aluminium structure. The tensile properties and resulting hardness are related to microstructural evolution induced by constrained groove pressing deformation. A substantial impact of straining upon the increasing in tensile strength was observed after the first deformation step (first pass) Further strain increase had an insignificant effect on tensile strength but was accompanied by ductility loss. The post deformation annealing effect was then explored with aim to increase the ductility. The results indicate that changes in strength and ductility may be related to formation of a bimodal structure in deformed plates.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

Studies on Related ms Magnitude Rate Models in Triangular Wave Unloading Section of Calcium Medium-Fine Sandstone

2010 ◽  
Vol 152-153 ◽  
pp. 164-170
Author(s):  
Jie Liu ◽  
Jian Lin Li ◽  
Ying Xia Li ◽  
Shan Shan Yang ◽  
Ji Fang Zhou ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Strain Curve ◽  
Experimental System ◽  
Constant Term ◽  
Lag Time ◽  
Vertical Force ◽  
Time Segment ◽  
Triangular Wave ◽  
Apparent Modulus ◽  
The Impact

Specific to the improvement in the present research of mechanical response under cyclic loading, this paper, taking the calcareous middle- coarse sandstone as the research subject and the RMT-150C experimental system in which data is recoded by ms magnitude as the platform, develops several related models concerning the unloading rate of triangle waves. The unloading process is divided into lag time segment and non-lag time segment, with criterions and related parameters provided as well. The term apparent elastic modulus is defined. The test data analysis shows that there exist a linear relationship between the apparent modulus and instant vertical force before load damage in non-lag time segment. On the preceding basis, a rate-dependent model of triangular wave un-installation section in non-lag time segment is established. Due to the inability of the loading equipment to accurately input the triangle wave, the average loading rate is amended and a constant term is added into it. The model is proved to be reliable, as the predicted value of the deformation rate and the stress strain curve coincides with measured value. At the same time, the impact of the lag time is pointed out quantitatively and a predication model of lag time segment is set up.

scholarly journals Anomalous Laterally Stressed Kinetically Trapped DNA Surface Conformations

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Valery V. Prokhorov ◽  
Nikolay A. Barinov ◽  
Kirill A. Prusakov ◽  
Evgeniy V. Dubrovin ◽  
Maxim D. Frank-Kamenetskii ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Mechanical Response ◽  
Persistence Length ◽  
Strong Impact ◽  
List Type ◽  
Surface Charges ◽  
Monomolecular Films ◽  
Chain Approximation ◽  
The Impact ◽  
Positively Charged

Highlights DNA kinking is inevitable for the highly anisotropic 1D–1D electrostatic interaction with the one-dimensionally periodically charged surface. The double helical structure of the DNA kinetically trapped on positively charged monomolecular films comprising the lamellar templates is strongly laterally stressed and extremely perturbed at the nanometer scale. The DNA kinetic trapping is not a smooth 3D—> 2D conformational flattening but is a complex nonlinear in-plane mechanical response (bending, tensile and unzipping) driven by the physics beyond the scope of the applicability of the linear worm-like chain approximation. Abstract Up to now, the DNA molecule adsorbed on a surface was believed to always preserve its native structure. This belief implies a negligible contribution of lateral surface forces during and after DNA adsorption although their impact has never been elucidated. High-resolution atomic force microscopy was used to observe that stiff DNA molecules kinetically trapped on monomolecular films comprising one-dimensional periodically charged lamellar templates as a single layer or as a sublayer are oversaturated by sharp discontinuous kinks and can also be locally melted and supercoiled. We argue that kink/anti-kink pairs are induced by an overcritical lateral bending stress (> 30 pNnm) inevitable for the highly anisotropic 1D-1D electrostatic interaction of DNA and underlying rows of positive surface charges. In addition, the unexpected kink-inducing mechanical instability in the shape of the template-directed DNA confined between the positively charged lamellar sides is observed indicating the strong impact of helicity. The previously reported anomalously low values of the persistence length of the surface-adsorbed DNA are explained by the impact of the surface-induced low-scale bending. The sites of the local melting and supercoiling are convincingly introduced as other lateral stress-induced structural DNA anomalies by establishing a link with DNA high-force mechanics. The results open up the study in the completely unexplored area of the principally anomalous kinetically trapped DNA surface conformations in which the DNA local mechanical response to the surface-induced spatially modulated lateral electrostatic stress is essentially nonlinear. The underlying rich and complex in-plane nonlinear physics acts at the nanoscale beyond the scope of applicability of the worm-like chain approximation.

Mechanical Response of Porous Copper Manufactured by Lost Carbonate Sintering Process

2007 ◽  
Vol 539-543 ◽  
pp. 1863-1867 ◽  
Author(s):  
X.F. Tao ◽  
Li Ping Zhang ◽  
Y.Y. Zhao
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Relative Density ◽  
Mechanical Response ◽  
Compaction Pressure ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Three Point Bending ◽  
Porous Copper ◽  
The Impact

This paper investigated the mechanical response of porous copper manufactured by LCS under three-point bending and Charpy impact conditions. The effects of the compaction pressure and K2CO3 particle size used in producing the porous copper samples and the relative density of the samples were studied. The apparent modulus, flexural strength and energy absorption capacity in three-point bending tests increased exponentially with increasing relative density. The impact strength was not markedly sensitive to relative density and had values within 7 – 9 kJ/m2 for the relative densities in the range 0.17 – 0.31. The amount of energy absorbed by a porous copper sample in the impact test was much higher than that absorbed in the three-point bending test, impling that loading strain rate had a significant effect on the deformation mechanisms. Increasing compaction pressure and increasing K2CO3 particle size resulted in significant increases in the flexural strength and the bending energy absorption capacity, both owing to the reduced sintering defects.

Application of Tailored Heat Treated Blanks under Quasi Series Conditions

2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Local Heat ◽  
Strength Distribution ◽  
Process Window ◽  
Short Term ◽  
Forming Process ◽  
Heat Treated ◽  
Set Up ◽  
The Impact

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.

Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors

Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Grazyna Koziol ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Electrical Resistance ◽  
Printed Circuit Boards ◽  
Base Material ◽  
Forming Process ◽  
Content Type ◽  
Thin Film Resistors ◽  
Embedded Resistors ◽  
The Impact

Purpose – The purpose of this paper is to investigate the influence of parameters of embedded resistive elements manufacturing process as well as the influence of environmental factors on their electrical resistance. The investigations were made in comparison to the similar constructions of discrete chip resistors assembled to standard printed circuit boards (PCBs). Design/methodology/approach – The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. The polymer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus standard assembled chip resistors on environmental exposure, the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles. Findings – The results show that the change of electrical resistance of embedded resistors, in dependence of construction and base material, is different and mainly not exceed the range of 3 per cent. The achieved results in reference to thin-film resistors are comparable with results for standard chip resistors. However, the results that were obtained for thick-film resistors with Ag and Ni/Au contacts are similar. It was not found the big differences between resistors with and without conformal coating. Research limitations/implications – The studies show that embedded resistors can be used interchangeably with chip resistors. It allows to save the area on the surface of PCB, occupied by these passive elements, for assembly of active elements (ICs) and thus enable to miniaturization of electronic devices. But embedding of passive elements into PCB requires to tackle the effect of each forming process steps on the operational properties. Originality/value – The technique of passive elements embedding into PCB is generally known; however, there are no detailed reports on the impact of individual process steps and environmental conditions on the stability of their electrical resistance. The studies allow to understand the importance of each factor process and the mechanisms of operational properties changes depending on the used materials.

scholarly journals Spent UO2 TRISO coated particles – instant release fraction and microstructure evolution

2015 ◽  
Vol 103 (6) ◽  
Author(s):  
Hildegard Curtius ◽  
Gabriele Kaiser ◽  
Norman Lieck ◽  
Murat Güngör ◽  
Martina Klinkenberg ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Spent Fuel ◽  
Coated Particles ◽  
The Impact ◽  
Very High

AbstractThe impact of burn-up on the instant release fraction (IRF) from spent fuel was studied using very high burn-up UO

Dieless Water Jet Incremental Micro-Forming

2018 ◽  
Author(s):  
Yi Shi ◽  
Jian Cao ◽  
Kornel F. Ehmann
Keyword(s):  
Process Parameters ◽  
Thin Shell ◽  
High Speed ◽  
Single Point ◽  
Sheet Thickness ◽  
Water Jet ◽  
Micro Forming ◽  
Forming Process ◽  
Thin Foils ◽  
High Pressure Water Jet

Compared to the conventional single-point incremental forming (SPIF) processes, water jet incremental micro-forming (WJIMF) utilizes a high-speed and high-pressure water jet as a tool instead of a rigid round-tipped tool to fabricate thin shell micro objects. Thin foils were incrementally formed with micro-scale water jets on a specially designed testbed. In this paper, the effects on the water jet incremental micro-forming process with respect to several key process parameters, including water jet pressure, relative water jet diameter, sheet thickness, and feed rate, were experimentally studied using stainless steel foils. Experimental results indicate that feature geometry, especially depth, can be controlled by adjusting the processes parameters. The presented results and conclusions provide a foundation for future modeling work and the selection of process parameters to achieve high quality thin shell micro products.

Sign in / Sign up

Export Citation Format

Share Document