Modelling the nano indentation behaviour of recast layer and heat affected zone on reverse micro EDMed hemispherical feature

2021 ◽  
pp. 1-15
Author(s):  
Tribeni Roy ◽  
Anuj Sharma ◽  
Prabhat Ranjan ◽  
R. Balasubramaniam
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Heat Affected Zone ◽  
Parent Material ◽  
Recast Layer ◽  
Machined Surface ◽  
Nano Indentation ◽  
Fea Simulation ◽  
Load Displacement ◽  
Good Agreement

Abstract Electrical discharge machined surfaces inherently possess recast layer on the surface with heat affected zone (HAZ) beneath it and these have a detrimental effect on the mechanical properties viz. hardness, elastic modulus, etc. It is very difficult to experimentally characterise each machined surface. Therefore, an attempt is made in this study to numerically calculate the mechanical properties of the parent material, HAZ and the recast layer on a hemispherical protruded micro feature fabricated by reverse micro EDM (RMEDM). In the 1st stage, nano indentation was performed to experimentally determine the load-displacement plots, elastic modulus and hardness of the parent material, HAZ and the recast layer. In the 2nd stage, FEA simulation was carried out to mimic the nano indentation process and determine the load-displacement plots for all the three cases viz. parent material, recast layer and HAZ. Results demonstrated that the load'displacement plots obtained from numerical model in each case was in good agreement with that of the experimental curves. Based on simulated load-displacement plots, hardness was also calculated for parent material, HAZ and the recast layer. A maximum of 11% error was observed between simulated values of hardness and experimentally determined values.

Effect of Oxygen and Nitrogen Doping on Mechanical Properties of Silicon Using Nanoindentation

2004 ◽  
Vol 821 ◽  
Author(s):  
A. Karoui ◽  
G. Rozgonyi ◽  
T. Ciszek
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Nitrogen Doping ◽  
High Hardness ◽  
Near Surface ◽  
Nano Indentation ◽  
Subsurface Region ◽  
Float Zone ◽  
Effect Of Oxygen ◽  
Scratch Tests

AbstractThe effects of oxygen and nitrogen on the mechanical properties of Czochralski (CZ) and float zone silicon have been studied using nano-indentation. Nitrogen free FZ Si exhibited low hardness of 6.49 GPa and elastic modulus of 104 GPa. When doped with 2×1015cm−3 nitrogen, FZ Si hardness and elastic modulus increased to 8.2 and 182 GPa, respectively. In the near-surface denuded zone of N-doped CZ Si (N-CZ) the hardness correlates well with the O and N profiles. Distinct high hardness points, found in the O- and N- rich subsurface region, were attributed to precipitates. Nano-scratch tests of N-CZ Si confirmed the existence of hard phases, mostly small precipitates, whose density, estimated to be 2×1013cm−3, is in the range of previously suggested nuclei density in as-grown N-CZ silicon.

Investigation of the Effect of Heating-Lines on Tensional Mechanical Properties of Sheet Metal after Laser Forming

2011 ◽  
Vol 117-119 ◽  
pp. 1666-1671
Author(s):  
Ai Hui Luo ◽  
Wen Jiao Dan ◽  
Wei Gang Zhang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Sheet Metal ◽  
Heat Affected Zone ◽  
Total Elongation ◽  
Laser Forming ◽  
Strain Hardening Exponent ◽  
Elongation Index ◽  
Hardening Coefficient

In this study，tensional mechanical properties of sheet metal with different heating-lines after laser forming are investigated. The basic mechanical properties of material (such as elastic modulus, yield strength, ultimate strength, TEI (total elongation index) and EIU (elongation index of uniform)) with different spacing between neighbored heating-lines and different heating-lines number are presented. The stress-strain curves are complied with a modified Swift law, where the hardening coefficient and strain hardening exponent of material are controlled by strain. The influence of heating-lines number on tensional mechanical properties of material is greater than that of the spacing between neighbored heating-lines. The results show that all mechanical properties are related to the distribution of microstructure in heat-affected zone after laser forming.

scholarly journals Inverse elastographic method for analyzing the ocular lens compression test

2017 ◽  
Vol 10 (06) ◽  
pp. 1742009 ◽  
Author(s):  
Matthew A. Reilly ◽  
Andre Cleaver
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Molecular Basis ◽  
Human Lens ◽  
Ocular Lens ◽  
Loss Of Function ◽  
Manual Compression ◽  
Wild Type ◽  
Genetic Manipulations ◽  
Good Agreement

The ocular lens stiffens dramatically with age, resulting in a loss of function. However, the mechanism of stiffening remains unknown, at least in part due to difficulties in making reliable measurements of the intrinsic mechanical properties of the lens. Recent experiments have employed manual compression testing to evaluate the stiffness of murine lenses which have genotypes pertinent to human lens diseases. These experiments compare the extrinsic stiffness of lenses from the genotype of interest to the wild-type lens in an effort to reach conclusions regarding the cellular or molecular basis of lens stiffening. However, these comparisons are confounded by alterations in lens size and geometry which invariably accompany these genetic manipulations. Here, we utilize manual lens compression to characterize the stiffness of a porcine lens and a murine lens. An inverse elastographic technique was then developed to estimate the intrinsic shear modulus of each lens as well as the elastic modulus of the lens capsule. The results were in good agreement with the previous literature values.

Harder and Stiffer Bone Osseointegrated to Roughened Titanium

2006 ◽  
Vol 85 (6) ◽  
pp. 560-565 ◽  
Author(s):  
F. Butz ◽  
H. Aita ◽  
C.J. Wang ◽  
T. Ogawa
Keyword(s):  
Surface Roughness ◽  
Elastic Modulus ◽  
Biomechanical Properties ◽  
Titanium Implants ◽  
Machined Surface ◽  
Implant Surface ◽  
Nano Indentation ◽  
Etched Surface ◽  
Post Implantation

Mechanisms underlying the beneficial anchorage of roughened titanium implants have not been identified. We hypothesized that the implant surface roughness alters intrinsic biomechanical properties of bone integrated to titanium. Nano-indentation performed on two- and four-week post-implantation bone specimens of rats revealed that bone integrated to acid-etched titanium was approximately 3 times harder than that integrated to the machined titanium, both at the osseointegration interface and at the inner area of the peri-implant bone. The hardness of the acid-etched surface-associated bone was equivalent to that of untreated cortical bone at week 4, while the bone hardness around the machined surface was equivalent to that of the untreated trabecular bone. The elastic modulus of the integrated bone was 1.5 to 2.5 times greater around the acid-etched surface than around the machined surface. Analysis of the data suggests that the implant surface roughness affects the biomechanical quality of osseo-integrated bone, and that the bone integrated to the acid-etched surface is harder and stiffer than the bone integrated to the machined surface.

Estimation of the Elastic Modulus and Moisture Absorption of Sisal Fibre

2013 ◽  
Vol 750-752 ◽  
pp. 204-209
Author(s):  
Yiou Shen ◽  
Yan Li ◽  
Feng Lv
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Moisture Absorption ◽  
Single Fibre ◽  
Geometrical Model ◽  
Natural Fibre ◽  
Sisal Fibre ◽  
Dimensional Parameters ◽  
Longitudinal Modulus ◽  
Good Agreement

Microstructures of sisal fibres were revealed optically. Statistics on dimensional parameters for sisal fibres were used to establish a geometrical model in order to estimate the elastic modulus and moisture absorption capability of sisal fibres. The single fibre tensile test was conducted on the sisal. The predicted longitudinal modulus and water absorption was in good agreement with experimental results. It was found that the lumen ratio is a significant factor in determine the mechanical properties of the natural fibre.

Recast layer and heat-affected zone structure of ultra-fined grained low-carbon steel machined by electrical discharge machining

2019 ◽  
Vol 234 (5) ◽  
pp. 933-944 ◽  
Author(s):  
Mohammad Sajjad Mahdieh
Keyword(s):  
Heat Affected Zone ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Recast Layer ◽  
Machining Process ◽  
Coarse Grain ◽  
Hardness Profile ◽  
Low Carbon ◽  
Machined Surface ◽  
Microstructural Changes

Ultra-fined grain materials are thermodynamically unstable and when they are exposed to a high external thermomechanical energy, such as electrical discharge machining process, many microstructural changes will occur in them. However, in the electrical discharge machining process, the recast layer and heat affected zone are the undesired and inevitable consequences of this process, which have several adverse effects on the surface layers of the workpiece including microstructural changes, grain growth, alternation of hardness, initiation of micro-cracks and changing the composition. All of which deteriorate the surface integrity. In this article, the effects of the electrical discharge machining process on the ultra-fined grain steel samples have been studied through investigating the microstructure of the recast layer and heat affected zone via scanning electron microscopy, optical microscopy and X-ray diffraction technique. The thickness of the recast layer and heat affected zone as well as the cracks’ density and the hardness profile of the ultra-fined grain samples was measured and the results were compared with coarse grain samples. Results show that the undesired effects of electrical discharge machining process on the ultra-fined grain samples are more considerable than the coarse grain ones; for instance, by comparison with coarse grain samples, relatively thicker recast layer and heat affected zone are formed in the ultra-fined grain samples, in which the microstructure changed more considerably. In addition, on one hand, the more extended cracks on the electrical discharge machined surface of the ultra-fined grain samples were observed, and on other hand, the hardness profile of the ultra-fined grain samples varies more noticeably from the surface to the depth.

Nanoindentation of Multi-Wall CNT Reinforced Al Composites

2010 ◽  
Vol 447-448 ◽  
pp. 549-553 ◽  
Author(s):  
Jin Zhi Liao ◽  
Jian Jun Pang ◽  
Ming Jen Tan
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Transverse Direction ◽  
Transverse Section ◽  
Hot Extrusion ◽  
Mechanical Tests ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Good Agreement

This work used nanoindentation to characterize the local mechanical properties of the multi-wall carbon nanotube (MWCNT) reinforced aluminum (Al) composites. The Al-MWCNT (0.5, 1.0 and 2.0 wt.%) specimens were fabricated by spark plasma sintering (SPS) followed by hot extrusion. Different local regions of the as-extruded and tensile-fractured specimen over the longitudinal and transverse section were studied by nanoindentation. The nanoindentation results were compared with the conventional macro- and mircoscopic mechanical tests, and were found in good agreement. The values of hardness (H) and elastic modulus (E) obtained reached maximum at the 0.5 wt.% MWCNT adding Al samples. E was highest in the necking region then decreased with increasing distance from the localized deformed region; while H varied in different regions. In the same region, H and V were higher in the longitudinal than those in the transverse direction, due to the texture hardening and alignment of CNT.

scholarly journals Microstructural Characterization and Mechanical Properties of Electron Beam Welded Joint of High Strength Steel Grade S690QL

2016 ◽  
Vol 61 (2) ◽  
pp. 1193-1200 ◽  
Author(s):  
S. Błacha ◽  
M. St. Węglowski ◽  
S. Dymek ◽  
M. Kopuściański
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
High Strength ◽  
Microstructural Characterization ◽  
Parent Material ◽  
Steel Grade ◽  
Fusion Line ◽  
Metallographic Examination

Abstract In the paper the results of metallographic examination and mechanical properties of electron beam welded joint of quenched and tempered steel grade S690QL are presented. Metallographic examination revealed that the concentrated electron beam significantly affect the changes of microstructure in the steel. Parent material as a delivered condition (quenched and tempered) had a bainitic-martensitic microstructure at hardness about 290 HV0.5. After welding, the microstructure of heat affected zone is composed mainly of martensite (in the vicinity of the fusion line) of hardness 420 HV0.5. It should be noted, however, that the microstructure of steel in the heat affected zone varies with the distance from the fusion line. The observed microstructural changes were in accordance with the CCT-S transformation diagram for the examined steel.

scholarly journals Study on Mechanical Properties of Carburized Layer Based on Nano-Indentation

2021 ◽  
Vol 31 (3) ◽  
pp. 131-137
Author(s):  
Zhenduo Sun ◽  
Shifeng Wang ◽  
Dongbo Hou
Keyword(s):  
Mechanical Properties ◽  
Pure Iron ◽  
Indentation Test ◽  
Experimental Result ◽  
Displacement Curve ◽  
Mechanical Parameters ◽  
Nano Indentation ◽  
Dimension Analysis ◽  
Carburized Layer ◽  
Load Displacement

The work aims to obtain the local mechanical parameters of carburized layer of CiNi steel. Tensile test and nano-indentation test were carried out for CrNi steel, stress-strain curve and load-displacement curve were then obtained. The finite element model of nano-indentation was built, and a model for obtaining the local mechanical parameters of carburized layer from load-displacement curve was established combined with dimension analysis. The mechanical parameters of pure iron and carburized layer of CrNi steel were calculated. The results show that, the dimension analysis model is accurate for predicting the mechanical properties of pure iron, the model accuracy is verified. The local mechanical parameters of carburized layer are predicted by the model, the simulated load-replacement curve based on the predicted mechanical parameters is in good agreement with the experimental result, it shows that the prediction result of the model is reasonable.

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