scholarly journals Mechanical Properties Evaluation of Bulk and Coated Material by Depth Sensing Indentation

Author(s):  
J.V. Fernandes ◽  
N.A. Sakharova ◽  
J.M. Antunes ◽  
M.C. Oliveir
2014 ◽  
Vol 606 ◽  
pp. 253-256 ◽  
Author(s):  
Martin Ovsik ◽  
Petr Kratky ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
...  

This article deals with the influence of different doses of Beta radiation to the structure and mico-mechanical properties of Low-density polyethylene (LDPE). Hard surface layers of polymer materials, especially LDPE, can be formed by radiation cross-linking by β radiation with doses of 33, 66 and 99 kGy. Material properties created by β radiation are measured by micro-hardness test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the LDPE tested. The highest values of micro-mechanical properties were reached at radiation dose of 66 and 99 kGy, when the micro-hardness values increased by about 21%. The changes were examined and confirmed by X-ray diffraction.


Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 968
Author(s):  
Dong Xing ◽  
Xinzhou Wang ◽  
Siqun Wang

In this paper, Berkovich depth-sensing indentation has been used to study the effects of the temperature-dependent quasi-static mechanical properties and creep deformation of heat-treated wood at temperatures from 20 °C to 180 °C. The characteristics of the load–depth curve, creep strain rate, creep compliance, and creep stress exponent of heat-treated wood are evaluated. The results showed that high temperature heat treatment improved the hardness of wood cell walls and reduced the creep rate of wood cell walls. This is mainly due to the improvement of the crystallinity of the cellulose, and the recondensation and crosslinking reaction of the lignocellulose structure. The Burgers model is well fitted to study the creep behavior of heat-treated wood cell walls under different temperatures.


2008 ◽  
Vol 373-374 ◽  
pp. 802-805 ◽  
Author(s):  
Hong Mei Wang ◽  
Pei Jing Shi ◽  
He Long Yu ◽  
Wei Zhang ◽  
Bin Shi Xu

As new engineering coatings get ever thinner and more technologically advanced, there is an increasing demand for accurate assessment of the mechanical properties of thin films. The rapidly expanding field of depth-sensing evaluation and techniques related provides a quantitative method for mapping the micro/nano mechanical properties. A new type of nano test system was introduced, the technology principle and the data analysis method were described. It was used to test the performance of brush-plated nanocomposite coatings, supersonic plasma-sprayed coatings and self-repairing microcapsule for corrosion-proof coatings, including the distribution of mechanical properties across the surface and the section and nanoindentation creep. The results show that nanoindentation techniques play an incomparable role in charactering the performance of surface coatings.


2016 ◽  
Vol 699 ◽  
pp. 37-42 ◽  
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Martin Reznicek

Radiation crosslinking of polyamidu 6 (PA 6) is a well-recognized modification of improving basic material characteristics. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. This research paper deals with the possible utilization of irradiated PA6. The material already contained a special cross-linking agent TAIC (5 volume %), which should enable subsequent cross-linking by ionizing β – radiation (15, 30 and 45 kGy). The effect of the irradiation on mechanical behavior of the tested PA 6 was investigated. Material properties created by β – radiation are measured by nanoindentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of nanoindentation test shows increasing in nanomechanical properties of surface layer. The highest values of nanomechanical properties were reached radiation dose of 45 kGy, when the nanomechanical values increased by about 95%. These results indicate advantage cross-linking of the improved mechanical properties.


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 1120-1121 ◽  
pp. 1163-1166 ◽  
Author(s):  
Petr Kratky ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Martin Ovsik ◽  
...  

Influence of mechanical properties of the hard surface layer of modified polyamide 6 is studied. Mechanical properties are acquired by nanohardness test with using the DSI method (Depth Sensing Indentation). Hard surface layers are created by radiation cross-linking technology. This technology allows polymer materials modification followed by the change of their end-use properties. The surface layer of polymer material is modified by ionizing β - radiation. When the polymer material is exposed to the β radiation, it is possible to observe changes of the surface layer at applied load. Radiation cross-linking usually improves strength, reduces creep, contributes to chemical resistance improvement, and in many cases improves tribological properties.


2010 ◽  
Vol 44-47 ◽  
pp. 2587-2591
Author(s):  
Xiu Fang Wang ◽  
Yi Wang Bao ◽  
Kun Ming Li ◽  
Yan Qiu ◽  
Xiao Gen Liu

The energy consumption of crushing is directly affected by the mechanical properties of cement materials. The elastic modulus, energy dissipation, recovery resistance and other mechanical properties of cement materials are evaluated based on the depth-sensing indentation method in this work. It is significant and efficient for engineering application. In results, the calculated elastic modulus is close to that measured by dynamic method, being used to verify the correctness of the calculated data. And the calculated energy dissipation of clinker is higher than that of limestone and granite, which can partially be used to explain why the grinding of clinker consumes a lot of energy in cement industry. The recovery resistance of clinker is almost identical to that of granite, more than that of limestone. It is found that the clinker, in contrast to granite and limestone, exhibits better plasticity and greater energy absorption capacity.


2018 ◽  
Vol 784 ◽  
pp. 153-158
Author(s):  
Ľubomír Ambriško ◽  
Ladislav Pešek

Depth-sensing indentation (DSI) is used in this work to determine the change of local mechanical properties by annealing of hot-dip galvanized IF steel sheets. The influence of annealing conditions (temperature and time) on: (i) coating composition; (ii) local mechanical properties and (iii) roughness of the coating surface was quantified. Annealing of steel samples (Ti-IF steel and Ti-Nb-P-IF steel alloyed with phosphorus) was performed with different holding times (10, 60, and 300 s) by both temperatures 450 and 550 °C. The zinc in coating transformed during annealing to the intermetallic phases ZnxFey. Annealed Zn-Fe coatings, wherein the iron concentration falls towards the surface, consist of different intermetallic phases.


2017 ◽  
Vol 891 ◽  
pp. 73-77
Author(s):  
Peter Burik ◽  
Ladislav Pešek ◽  
Zuzana Andršová ◽  
Pavel Kejzlar

Nanomechanical testing using depth sensing indentation (DSI) provides a straightforward solution for characterizing of mechanical properties (indentation hardness HIT, Young’s modulus EIT, indentation energy: total Wtotal, elastic Welast, plastic Wplast) of homogeneous (bulk) materials. However, real materials such as multi-phase steels are a heterogeneous material on the microscopic scale (microstructure). We need to know the local mechanical properties of each phase separately in those materials for reasons development of new materials and for modeling. Mechanical properties of each phase separately in multiphase materials are difficult or even impossible to examine in bulk material ex situ.In this paper we describe the technique for measuring the mechanical properties of each phase separately in multiphase steel by two-dimensional mapping tool. This approach relies on large arrays of nanoindentations (known as grid indentation) and statistical analysis of the resulting data [1, 2]. The aim of this investigation is to optimize the parameters of the grid indentation for a given microstructure of steel sheets.


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