Josef Zapletal

Dr. Josef Zapletal


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 April 2017 in Materials & Design
Verified
Journal Article
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IMIgor Moravcik
Igor Moravcik
JCJan CIZEK
Jan CIZEK
JZJosef Zapletal
Josef Zapletal
ZKZuzana Kovacova
Zuzana Kovacova
JVJozef Veselý
Jozef Veselý
IDIvo Dlouhy
Ivo Dlouhy

31 October 2017 in Metals
Verified
Journal Article
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MBMatěj Březina
Matěj Březina
JMJozef Minda
Jozef Minda
PDPavel Doležal
Pavel Doležal
MHMichaela Hasoňová
Michaela Hasoňová
SFStanislava Fintová
Stanislava Fintová
PPPetr Ptáček
Petr Ptáček
Magnesium with its mechanical properties and nontoxicity is predetermined as a material for biomedical applications; however, its high reactivity is a limiting factor for its usage. Powder metallurgy is one of the promising methods for the enhancement of material mechanical properties and, due to the introduced plastic deformation, can also have a positive influence on corrosion resistance. Pure magnesium samples were prepared via powder metallurgy. Compacting pressures from 100 MPa to 500 MPa were used for samples’ preparation at room temperature and elevated temperatures. The microstructure of the obtained compacts was analyzed in terms of microscopy. The three-point bendisng test and microhardness testing were adopted to define the compacts’ mechanical properties, discussing the results with respect to fractographic analysis. Electrochemical corrosion properties analyzed with electrochemical impedance spectroscopy carried out in HBSS (Hank’s Balanced Salt Solution) and enriched HBSS were correlated with the metallographic analysis of the corrosion process. Cold compacted materials were very brittle with low strength (up to 50 MPa) and microhardness (up to 50 HV (load: 0.025 kg)) and degraded rapidly in both solutions. Hot pressed materials yielded much higher strength (up to 250 MPa) and microhardness (up to 65 HV (load: 0.025 kg)), and the electrochemical characteristics were significantly better when compared to the cold compacted samples. Temperatures of 300 °C and 400 °C and high compacting pressures from 300 MPa to 500 MPa had a positive influence on material bonding, mechanical and electrochemical properties. A compacting temperature of 500 °C had a detrimental effect on material compaction when using pressure above 200 MPa.

27 September 2017 in Metals
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Journal Article
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MHMichaela Hasoňová
Michaela Hasoňová
PDPavel Doležal
Pavel Doležal
SFStanislava Fintová
Stanislava Fintová
MBMatěj Březina
Matěj Březina
JZJosef Zapletal
Josef Zapletal
JWJaromír Wasserbauer
Jaromír Wasserbauer
The use of zinc-based materials as biodegradable materials for medical purposes is offered as a possible alternative to corrosion-less resistant magnesium-based materials. Zinc powders with two different particle sizes (7.5 µm and 150 µm) were processed by the methods of powder metallurgy: cold pressing, cold pressing followed by sintering and hot pressing. The microstructure of prepared materials was evaluated in terms of light optical microscopy, and the mechanical properties were analyzed with Vickers microhardness testing and three-point bend testing. Fractographic analysis of broken samples was performed with scanning electron microscopy. Particle size was shown to have a significant effect on compacts mechanical properties. The deformability of 7.5 µm particle size powder was improved by increased temperature during the processing, while in the case of larger powder, no significant influence of temperature was observed. Bending properties of prepared materials were positively influenced by elevated temperature during processing and correspond to the increasing compacting pressures. Better properties were achieved for pure zinc prepared from 150 µm particle size powder compared to materials prepared from 7.5 µm particle size powder.

1 March 2013 in Materials & Design (1980-2015)
Verified
Journal Article
Closed access
MHMiroslava Horynová
Miroslava Horynová
JZJosef Zapletal
Josef Zapletal
PDPavel Doležal
Pavel Doležal
PGPavel Gejdoš
Pavel Gejdoš

28 October 2016 in Materials
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Journal Article
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PDPavel Doležal
Pavel Doležal
JZJosef Zapletal
Josef Zapletal
SFStanislava Fintová
Stanislava Fintová
ZTZuzanka Trojanová
Zuzanka Trojanová
MGMiroslav Greger
Miroslav Greger
TPTomáš Podrábský
Tomáš Podrábský
New Mg-3Zn-2Ca magnesium alloy was prepared using different processing techniques: gravity casting as well as squeeze casting in liquid and semisolid states. Materials were further thermally treated; thermal treatment of the gravity cast alloy was additionally combined with the equal channel angular pressing (ECAP). Alloy processed by the squeeze casting in liquid as well as in semisolid state exhibit improved plasticity; the ECAP processing positively influenced both the tensile and compressive characteristics of the alloy. Applied heat treatment influenced the distribution and chemical composition of present intermetallic phases. Influence of particular processing techniques, heat treatment, and intermetallic phase distribution is thoroughly discussed in relation to mechanical behavior of presented alloys.

7 September 2019 in Journal of Engineering Materials and Technology
Verified
Journal Article
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PKPetr Kubík
Petr Kubík
FŠFrantišek Šebek
František Šebek
JZJosef Zapletal
Josef Zapletal
JPJindřich Petruška
Jindřich Petruška
TNTomáš Návrat
Tomáš Návrat
FEFrantiek Ebek
Frantiek Ebek
The ductile failure predictions have been an issue in many engineering applications. It begins with a design of machines and tools, continues with an evaluation of manufacturing processes, and last but not least ends with the assessment of various structures. The paper deals with a predictability of used criteria for a random structure of aluminum alloy 2024-T351, which was performed under the conditions of room temperature three-point bending. The bi-failure mode creates a space for the numerical studies of various approaches and gives an insight into the model performance. The plasticity was described by Lode-dependent yield criterion, which was coupled with several pressure and Lode-dependent fracture models to form a continuum damage mechanics approach via the material weakening. It was incorporated through a nonlinear damage accumulation, which was finally implemented using Fortran 77 subroutine into abaqus/explicit. All the models exhibited a good ability of crack onset prediction in terms of the force responses and realistic predictability of the crack propagation. The field of deformations was successfully compared with experimental data obtained by an optical method.