The Influence of Surface Quality on Flow Length and Micro-Mechanical Properties of Polycarbonate

This study describes the influence of polymer flow length on mechanical properties of tested polymer, specifically polycarbonate. The flow length was examined in a spiral shaped mould. The mould cavity’s surface was machined by several methods, which led to differing roughness of the surface. The cavity was finished by milling, grinding and polishing. In order to thoroughly understand the influence of the mould surface quality on the flow length, varying processing parameters, specifically the pressure, were used. The polymer part was divided into several segments, in which the micro-mechanical properties, such as hardness and indentation modulus were measured. The results of this study provide interesting data concerning the flow length, which was up to 3% longer for rougher surfaces, but shorter in cavities with polished surface. These results are in disagreement with the commonly practiced theory, which states that better surface quality leads to greater flow length. Furthermore, evaluation of the micro-mechanical properties measured along the flow path demonstrated significant variance in researched properties, which increased by 35% (indentation hardness) and 86% by indentation modulus) in latter segments of the spiral in comparison with the gate.

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Effect of Different Factors on Measured Values of Indentation Hardness of Interstitial Free Steel by Depth Sensing Indentation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.784.49 ◽

2018 ◽

Vol 784 ◽

pp. 49-54

Author(s):

Peter Burik ◽

Ladislav Pešek ◽

Zuzana Andršová ◽

Pavel Kejzlar

Keyword(s):

Mechanical Properties ◽

Sample Surface ◽

Indentation Hardness ◽

Indentation Modulus ◽

Interstitial Free ◽

Depth Sensing ◽

Multiphase Materials ◽

Material Characteristics ◽

Straightforward Solution ◽

Characterization Of Materials

Nanomechanical testing using depth sensing indentation (DSI) provides a straightforward solution for quantitatively characterizing each of phases in microstructure because it is very powerful technique for characterization of materials in small volumes. Measuring the local properties (indentation hardness HIT, indentation modulus EIT, indentation energy: total Wtotal, elastic Welast, plastic Wplast) of each microstructure component separately in multiphase materials gives information that is valuable for the development of new materials and for modelling. The mechanical properties of materials measured by DSI are affected by the experimental procedure, by the measurement conditions and factors which result from the material characteristics and device construction. We have to determine the effect of individual factors on the measurement in order to reach the repeatability and to allow the comparing the mechanical properties of the material. The aim of this investigation is to determine the measurement factors that affect indentation hardness of individual microstructural components and global mechanical properties of thin steel sheets. We investigated the factors which result from the material characteristics (crystallographic orientation of grain, grain boundary and anisotropy), preparation of the sample surface (roughness of sample surface) and method of measurement (pile-up, ISE).

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Study on the Influence of the Grind Percentage Over the Surface Hardness and Modulus of Elasticity of Parts Made of ABS, P6.6 and POM through Nanoindentation

Materiale Plastice ◽

10.37358/mp.19.1.5124 ◽

2019 ◽

Vol 56 (1) ◽

pp. 65-70

Author(s):

Gheorghe Radu Emil Maries ◽

Constantin Bungau ◽

Dan Chira ◽

Traian Costea ◽

Danut-Eugeniu Mosteanu

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Surface Hardness ◽

Acrylonitrile Butadiene Styrene ◽

The Other ◽

Indentation Hardness ◽

Indentation Modulus ◽

Maximum Hardness ◽

New Material ◽

Butadiene Styrene

This paper analyzes the indentation hardness and the indentation elastic modulus variation depending on the variation of the grind percentage of polymer, when the other factors that can influence the injection molding remain unchanged. The analyzed polymers were: acrylonitrile butadiene styrene ABS MAGNUM 3453, polyamide PA 6.6 TECHNYL AR218V30 Blak and polyoxymethylene POM EUROTAL C9 NAT. The samples that were studied had different compositions in new and grinding material. The G-Series Basic Hardness Modulus at a Depth method was used. The increase of the grind percentage of ABS (from 0 to 100 %) leads to insignificant changes in the indentation hardness, indentation modulus, and maximum force applied to samples of tested material. The maximum hardness (0.137 GPa) of PA 6.6 is recorded in the case of the sample with 80% grind content, and the maximum hardness of POM is recorded as well in the case of the sample with 80% grind content, as being 0.215 GPa. The variation of the grind content in the analyzed samples determines changes in the evaluated parameters, depending on the type of polymer. Combining the new material with grind in proportions experimentally established for each techno polymer leads to changes in their mechanical properties.

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Improving Surface Properties of Linear Polyethylene by Radiation Measured by Ultra-Nano Indentation Test

Materials Science Forum ◽

10.4028/www.scientific.net/msf.952.172 ◽

2019 ◽

Vol 952 ◽

pp. 172-179

Author(s):

Martin Ovsik ◽

Michal Stanek ◽

Adam Dockal ◽

Martin Reznicek ◽

Lenka Hylova

Keyword(s):

Mechanical Properties ◽

Surface Properties ◽

Three Dimensional ◽

Indentation Test ◽

Optimal Dose ◽

Indentation Hardness ◽

Indentation Modulus ◽

Deformation Work ◽

Correct Function ◽

Economical Aspect

Surface properties are important aspect for correct function of construction (technical) parts. By improving mechanical properties of surface, an increase of abrasion resistance and wear resistance is reached. Longevity and economical aspect have an important role in final useful properties of product. Measurement of surface properties was done by ultra-nanoindentation technique (UNHT3), this is the best tool available right now, this technique is based on instrumented testing. Surface properties were modified by ionized radiation, that caused the creation of crosslinked structure in polyethylene. During radiation a three dimensional network is created, that improves final properties of product such as: hardness, elasticity modulus, thermal stability, etc. During ionized radiation there are two actions that take place at the same time, crosslinking and degradation. Goal of this paper is to consider how radiation intensity affects surface properties (indentation hardness, indentation modulus, deformation work, etc.) Another goal of this paper is to find out the optimal dose of radiation, that will cause more three dimensional crosslinking and less degradation as degradation causes decrease in mechanical properties.

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The Behaviour of Cross-Linking Filled PA66 by Micro-Indentation Test

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.699.43 ◽

2016 ◽

Vol 699 ◽

pp. 43-48

Author(s):

Martin Ovsik ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

Vojtech Senkerik

Keyword(s):

Mechanical Properties ◽

Surface Layer ◽

Glass Fiber ◽

Indentation Test ◽

Polymer Materials ◽

Beta Radiation ◽

Indentation Hardness ◽

Indentation Modulus ◽

Polyamide 66 ◽

Depth Sensing

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Micro-mechanical changes in the surface layer of glass-fiber filled PA 66 modified by beta radiation were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The specimens were prepared by injection technology and subjected to radiation doses of 0, 33, 66 nad 99 kGy. The change of micro-mechanical properties is greatly manifested mainly in the surface layer of the modified polypropylene where a significant growth of micro-hardness values can be observed. Indentation modulus increased from 1.8 to 3.0 GPa (increasing about 66%) and indentation hardness increased from 87 to 157 MPa (increasing about 80%). This research paper studies the influence of the dose of irradiation on the micro-mechanical properties of semi-crystalline polyamide 66 filled by 30% glass fiber at room temperature. The study is carried out due to the ever-growing employment of this type of polymer.

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Micro-Hardness of PA6 Influenced by Beta Irradiation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.752-753.322 ◽

2015 ◽

Vol 752-753 ◽

pp. 322-325

Author(s):

Martin Ovsik ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

Martin Reznicek ◽

...

Keyword(s):

Mechanical Properties ◽

Crosslinking Agent ◽

Polyamide 6 ◽

Point Of View ◽

Polymer Chains ◽

Indentation Creep ◽

Indentation Hardness ◽

Indentation Modulus ◽

Micro Hardness ◽

Depth Sensing

In this paper, the effect of the electron beam irradiation on the indentation hardness, indentation modulus and indentation creep have been studied by means of the Depth sensing indentation (DSI). Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation doses of 33, 66 and 99 kGy were used for unfilled polyamide 6 with the 7% crosslinking agent (triallyl isocyanurate). Beta irradiation of the examined thermoplastic caused the growth of values of material parameters as micro-hardness, indentation modulus or indentation creep etc. From this point of view, there may be new application in areas with mechanical properties higher than their original properties. This study compared the mechanical properties of irradiated and non-irradiated PA6.

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Mapping of the Micro-Mechanical Properties of Human Root Dentin by Means of Microindentation

Materials ◽

10.3390/ma14030505 ◽

2021 ◽

Vol 14 (3) ◽

pp. 505

Author(s):

Michael Kucher ◽

Martin Dannemann ◽

Niels Modler ◽

Martina Romy Bernhard ◽

Christian Hannig ◽

...

Keyword(s):

Mechanical Properties ◽

Indentation Creep ◽

Indentation Hardness ◽

Indentation Modulus ◽

Microstructural Alterations ◽

Starting Point ◽

Human Dentin ◽

Root Dentin ◽

Cervical Root ◽

Martens Hardness

The extensive knowledge of root dentin’s mechanical properties is necessary for the prediction of microstructural alterations and the teeth’s deformations as well as their fracture behavior. Standardized microindentation tests were applied to apical, medial, and cervical root sections of a mandibular human first molar to determine the spatial distribution of the hard tissue’s properties (indentation modulus, indentation hardness, Martens hardness, indentation creep). Using an indentation mapping approach, the inhomogeneity of mechanical properties in longitudinal as well as in transversal directions were measured. As a result, the tooth showed strongly inhomogeneous material properties, which depended on the longitudinal and transversal positions. In the transversal cutting planes of the cervical, medial, apical sections, the properties showed a comparable distribution. A statistical evaluation revealed an indentation modulus between 12.2 GPa and 17.8 GPa, indentation hardness between 0.4 GPa and 0.64 GPa and an indentation creep between 8.6% and 10.7%. The established standardized method is a starting point for further investigations concerning the intensive description of the inhomogeneous mechanical properties of human dentin and other types of dentin.

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Micro-Indentation Test of Cross-Linking Polyethylene

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1120-1121.1175 ◽

2015 ◽

Vol 1120-1121 ◽

pp. 1175-1178

Author(s):

Martin Ovsik ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

Martin Reznicek

Keyword(s):

Mechanical Properties ◽

Mechanical Behavior ◽

Indentation Test ◽

Basic Material ◽

Cross Linking ◽

Indentation Hardness ◽

Indentation Modulus ◽

Linear Polyethylene ◽

Radiation Crosslinking ◽

Micro Indentation

Radiation crosslinking of linear polyethylene (LLDPE) is a well-recognized modification of improving basic material characteristics. This research paper deals with the utilization of electron beam irradiated LLDPE on the micro-indentation test. The effect of the irradiation on mechanical behavior of the tested polyethylene was investigated. The results indicate that the mechanical behavior, highly depends on the intensity of irradiation. Toughness and hardness grew with increasing dose of the irradiation LLDPE. Indentation modulus increased from 0.25 to 0.28 GPa and indentation hardness increased from 21.89 to 26.25 MPa. These results indicate advantage crosslinking of the improved mechanical properties.

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The Influence of the Third Element on Nano-Mechanical Properties of Iron Borides FeB and Fe2B Formed in Fe-B-X (X = C, Cr, Mn, V, W, Mn + V) Alloys

Materials ◽

10.3390/ma13184155 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4155

Author(s):

Ivana Kirkovska ◽

Viera Homolová ◽

Ivan Petryshynets ◽

Tamás Csanádi

Keyword(s):

Mechanical Properties ◽

Indentation Size Effect ◽

Microstructural Characterization ◽

Indentation Hardness ◽

Indentation Modulus ◽

Instrumented Indentation ◽

X Ray Diffraction ◽

Alloying Element ◽

X Ray

In this study, the influence of alloying elements on the mechanical properties of iron borides FeB and Fe2B formed in Fe-B-X (X = C, Cr, Mn, V, W, Mn + V) alloys were evaluated using instrumented indentation measurement. The microstructural characterization of the alloys was performed by means of X-ray diffraction and scanning electron microscope equipped with an energy dispersive X-ray analyzer. The fraction of the phases present in the alloys was determined either by the lever rule or by image analysis. The hardest and stiffest FeB formed in Fe-B-X (X = C, Cr, Mn) alloys was observed in the Fe-B-Cr alloys, where indentation hardness of HIT = 26.9 ± 1.4 GPa and indentation modulus of EIT = 486 ± 22 GPa were determined. The highest hardness of Fe2B was determined in the presence of tungsten as an alloying element, HIT = 20.8 ± 0.9 GPa. The lowest indentation hardness is measured in manganese alloyed FeB and Fe2B. In both FeB and Fe2B, an indentation size effect was observed, showing a decrease of hardness with increasing indentation depth.

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Nano-indentation test of electron beam irradiated polyamide 11

MATEC Web of Conferences ◽

10.1051/matecconf/201821002037 ◽

2018 ◽

Vol 210 ◽

pp. 02037

Author(s):

Martin Ovsik ◽

Lenka Hylova ◽

Ivan Hudec ◽

Adam Dockal

Keyword(s):

Mechanical Properties ◽

Electron Beam ◽

Indentation Test ◽

Polymeric Materials ◽

Beta Radiation ◽

High Tech ◽

Indentation Hardness ◽

Indentation Modulus ◽

Beam Radiation ◽

Polyamide 11

This article deals with the influence of electron beam radiation on nano-mechanical properties and the structure of polyamide 11. Crosslinking of polymers is a process, during which macromolecular chains start to connect to each other and the spatial network creates in the structure. During the action of the ionizing radiation two actions can occur: crosslinking and scission of macromolecules – degradation. Both these processes run parallel. Using the crosslinking technology the standard and construction polymer can obtain the more “expensive” high-tech polymeric materials properties and thus replace these materials in many applications. Tested material was irradiated by different doses of beta radiation (33, 66 and 99 kGy). The nano-mechanical properties were measured using DSI method, which fluently records the change of the indentation in time. From this dependence it is possible to determine nano-mechanical properties such as indentation hardness, indentation modulus etc. During results consideration it is obvious that irradiation acts on each polymer differently, but always when the optimal dose was found, nano-mechanical properties increased up to 34 %. The changes of nano-mechanical properties were confirmed by structural measurement when the change of hardness and modulus corresponded to gel content.

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Selective laser melting (SLM) of pure gold for manufacturing dental crowns

Rapid Prototyping Journal ◽

10.1108/rpj-03-2013-0034 ◽

2014 ◽

Vol 20 (6) ◽

pp. 471-479 ◽

Cited By ~ 11

Author(s):

Mushtaq Khan ◽

Phill Dickens

Keyword(s):

Mechanical Properties ◽

Layer Thickness ◽

Surface Quality ◽

Selective Laser Melting ◽

Processing Parameters ◽

Pure Gold ◽

Laser Melting ◽

Content Type ◽

Dental Crowns ◽

Suitable Processing

Purpose – This paper aims to present the application aspect of the work to manufacturing premolar and molar dental crowns by selective laser melting (SLM) of pure gold. Over the years different metals have been processed using laser-based Additive Manufacturing processes, but very little work has been published on the SLM of gold (Au). Previously published work presented suitable processing parameters for SLM of pure gold. Design/methodology/approach – Suitable processing parameters were used to manufacture premolar and molar dental crowns using SLM system. Different layer thickness was used to analyse the effect on surface quality of crowns. Mechanical properties are checked using nanoindentation and micro Computerized Tomography scanning. Findings – Dental crowns were successfully manufacturing using new build platform and suitable processing parameters. Parts were manufacturing using minimal supports which prevented parts from damaging during removal. A bed temperature of 100°C was found suitable for reducing warpage in the layers. Layer thickness of 50μm was found to have better surface quality and structural integrity as compared to 75μm. Porosity was found to be predominantly inter-layer. Small difference in mechanical properties of dental crowns is associated with the laser processing. Originality/value – This research is the first of its kind which presents dental crown manufacturing using SLM of pure gold.

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