scholarly journals Nano-indentation test of electron beam irradiated polyamide 11

2018 ◽  
Vol 210 ◽  
pp. 02037
Author(s):  
Martin Ovsik ◽  
Lenka Hylova ◽  
Ivan Hudec ◽  
Adam Dockal

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.

2016 ◽  
Vol 699 ◽  
pp. 43-48
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Vojtech Senkerik

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.


2019 ◽  
Vol 952 ◽  
pp. 172-179
Author(s):  
Martin Ovsik ◽  
Michal Stanek ◽  
Adam Dockal ◽  
Martin Reznicek ◽  
Lenka Hylova

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.


2015 ◽  
Vol 1120-1121 ◽  
pp. 1175-1178
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Martin Reznicek

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.


2018 ◽  
Vol 784 ◽  
pp. 38-43
Author(s):  
Marek Vojtko ◽  
Ján Balko ◽  
Martin Fides ◽  
Liudmila Vojtkova

The aim of this work is indentation study of local mechanical properties of Cu-22Zn-4.6Al alloy, which has significant shape memory effect after quenching from dual α + β phase region. The study was carried out on the samples with thermoelastic and non-thermoelastic martensite in the structure, which were obtained by quenching from various temperatures. A different behavior concerning mechanical properties measurements of α phase and β phase transformed to martensite after quenching from various temperatures was found out. It was observed almost no change of mechanical properties of α phase, whereas indentation hardness HIT and indentation modulus EIT raised with increasing quenching temperature. Also some serious differences were observed at indentation test of thermoelastic and non-thermoelastic martensite.


2018 ◽  
Vol 784 ◽  
pp. 49-54
Author(s):  
Peter Burik ◽  
Ladislav Pešek ◽  
Zuzana Andršová ◽  
Pavel Kejzlar

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).


2015 ◽  
Vol 752-753 ◽  
pp. 363-368
Author(s):  
David Manas ◽  
Martin Ovsik ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Petr Fiala ◽  
...  

Micromechanical changes in the surface layer of glass-filled PA-6 modified by beta radiation were measured by instrumented test of microhardness. The specimens were prepared by injection technology and subjected to radiation doses of 0, 66, 99, 132 kGy. Measurements of microhardness showed considerable changes of behavior of surface layer in middle as well as high radiation doses with higher values of indentation hardness and stiffness.


2011 ◽  
Vol 364 ◽  
pp. 427-433 ◽  
Author(s):  
Mohamad Yatim Norazlina ◽  
Yusof Faridah ◽  
Chantara Thevy Ratnam ◽  
Iis Sopyan

The effect of irradiation on the mechanical properties of Epoxidized Natural Rubber/Ethylene Vinyl Acetate/Carbon Nanotubes (ENR/EVA/CNTs) nanocomposites were investigated. CNTs at various amount (2, 3, 4 and 6 wt%) were incorporated into ENR50 by solvent casting method. The ENR/CNTs were then blended with EVA by mixing in a Brabender Plasticoder at 120°C. Next, the samples were irradiated by using electron beam with 3 MeV electron beam machine in a dose range of 50 to 200 kGy. The mechanical properties such as tensile strength (Ts), modulus at 100% elongation (M100), elongation at break (Eb) and hardness of reinforced ENR/EVA/CNTs nanocomposites were studied as a function of radiation dose. It was found that, the Ts and M100 has increased almost 2 times compared to the nanocomposites without irradiation up to 150 kGy dose of radiation, and a downward trend thereafter. Gel fraction further confirmed the powerful energy of electron beam radiation result in irradiation-induced crosslinking and further enhanced mechanical properties of the nanocomposites.


2019 ◽  
Vol 56 (1) ◽  
pp. 65-70
Author(s):  
Gheorghe Radu Emil Maries ◽  
Constantin Bungau ◽  
Dan Chira ◽  
Traian Costea ◽  
Danut-Eugeniu Mosteanu

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.


Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 786 ◽  
Author(s):  
Giovanni Maizza ◽  
Antonio Caporale ◽  
Christian Polley ◽  
Hermann Seitz

The performance of two selective electron beam melting operation modes, namely the manual mode and the automatic ‘build theme mode’, have been investigated for the case of a Ti-6Al-4V alloy (45–105 μm average particle size of the powder) in terms of porosity, microstructure, and mechanical properties. The two operation modes produced notable differences in terms of build quality (porosity), microstructure, and properties over the sample thickness. The number and the average size of the pores were measured using a light microscope over the entire build height. A density measurement provided a quantitative index of the global porosity throughout the builds. The selective-electron-beam-melted microstructure was mainly composed of a columnar prior β-grain structure, delineated by α-phase boundaries, oriented along the build direction. A nearly equilibrium α + β mixture structure, formed from the original β-phase, arranged inside the prior β-grains as an α-colony or α-basket weave pattern, whereas the β-phase enveloped α-lamellae. The microstructure was finer with increasing distance from the build plate regardless of the selected build mode. Optical measurements of the α-plate width showed that it varied as the distance from the build plate varied. This microstructure parameter was correlated at the sample core with the mechanical properties measured by means of a macro-instrumented indentation test, thereby confirming Hall-Petch law behavior for strength at a local scale for the various process conditions. The tensile properties, while attesting to the mechanical performance of the builds over a macro scale, also validated the indentation property measurement at the core of the samples. Thus, a direct correlation between the process parameters, microstructure, porosity, and mechanical properties was established at the micro and macro scales. The macro-instrumented indentation test has emerged as a reliable, easy, quick, and yet non-destructive alternate means to the tensile test to measure tensile-like properties of selective-electron-beam-melted specimens. Furthermore, the macro-instrumented indentation test can be used effectively in additive manufacturing for a rapid setting up of the process, that is, by controlling the microscopic scale properties of the samples, or to quantitatively determine a product quality index of the final builds, by taking advantage of its intrinsic relationship with the tensile properties.


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