<abstract xmlns="http://www.w3.org/1999/xhtml"> The paper is presented the development and method of production of modern, Ni-free sintered structural steels which contain carbide forming alloying elements (Cr) with high affinity for oxygen (Cr, Mn) and the much smaller additive of an expensive alloying element (Mo), enabling the production of structural sintered steels in commercial belt furnaces, using safe sintering atmospheres. The investigations reported deal with the analysis of microstructure and mechanical properties of these sintered structural steels produced in different processing conditions, especially modification of chemical composition of sintering atmosphere and also the connections between the microstructure of sintered material and its mechanical properties. This analysis was done to propose the appropriate chemical composition of sintered Ni-free steels with properties which are comparable or even better than those of sintered structural steels containing rich and carcinogenic nickel. The investigations of PM Mn- Cr-Mo steels were preceded by those on Mn steels.</abstract>

Sintered Structural Steels Containing Mn, Cr And Mo – The Summary of the Investigations

<abstract xmlns="http://www.w3.org/1999/xhtml"> Nitrogen is usually regarded as an inert sintering atmosphere for PM steels; however, this cannot be taken for granted in particular for steels alloyed with nitride forming elements. Among those elements, chromium has become more and more important as an alloying element in sintered low alloy structural steels in the last decade due to the moderate alloying cost and the excellent mechanical properties obtainable, in particular when sinter hardening is applied. The high affinity of Cr to oxygen and the possible ways to overcome related problems have been the subject of numerous studies, while the fact that chromium is also a fairly strong nitride forming element has largely been neglected at least for low alloy steel grades, although frequently used materials like steels from Cr and Cr-Mo prealloyed powders are commonly sintered in atmospheres consisting mainly of nitrogen.In the present study, nitrogen pickup during sintering at different temperatures and for varying times has been studied for Cr-Mo prealloyed steel grades as well as for unalloyed carbon steel. Also the effect of the cooling rate and its influence on the properties, of the microstructure and the composition have been investigated. It showed that the main nitrogen uptake occurs not during isothermal sintering but rather during cooling. It could be demonstrated that a critical temperature range exists within which the investigated CrM-based steel is particularly sensitive to nitrogen pickup.</abstract>

Technische Universität Wien, Getreidemarkt 9//164 CT, A-1060 Vienna, Austria

now: MIBA Sinter Austria GmbH, A-4655 Vorchdorf,

Höganäs AB, Bruksgatan 35, S-263 83 Höganäs,

Institute of Materials Research SAS, Watsonova 47, SK-040 01 Košice,

Reaction of Unalloyed and Cr-Mo Alloyed Steels with Nitrogen from the Sintering Atmosphere

<abstract xmlns="http://www.w3.org/1999/xhtml"> At present biodegradable implants received increased attention due to their use in various fields of medicine. This work is dedicated to testing of biodegradable materials which could be used as bone implants. The samples were prepared from the carbonyl iron powder by replication method and surface polymer film was produced through sol-gel process. Corrosion testing was carried out under static conditions during 12 weeks in Hank’s solution. The quantity of corrosion products increased with prolonging time of static test as it can be concluded from the results of EDX analysis. The degradation of open cell materials with polyethylene glycol coating layer was faster compared to uncoated Fe sample. Also the mass losses were higher for samples with PEG coating. The polymer coating brought about the desired increase in degradation rate of porous iron material.</abstract>

Department of Physical Chemistry, Faculty of Science, P.J. Šafárik University, Moyzesova 11, SK-04154 Košice,

Institute of Materials Research, Slovak Academy of Science, Watsonova 47, SK-04353 Košice,

Institute of Geotechnics, Slovak Academy of Science, Watsonova 47, SK-04353 Košice,

Static Corrosion Test of Porous Iron Material with Polymer Coating

<abstract xmlns="http://www.w3.org/1999/xhtml"> The fields of soft magnetic composites and powder metallurgy technologies have a powerful potential to redesign the way of electric motor preparation, and will continue to grow for years to come. A design of the novel soft microcomposite material composed of spherical FeSi particles and Ni0.3Zn0.7Fe2O4 ferrite nanofibers is reported together with a characterization of basic mechanical and electrical properties. The needle-less electrospinning method was used for a preparation of Ni0.3Zn0.7Fe2O4 ferrite nanofibers, which has a spinel-type crystal structure as verified by XRD and TEM analysis. The dielectric coating was prepared by mixing of nanofibers with glycerol and ethanol because of safe manipulation with fumed fibers and homogeneous distribution of the coating around the FeSi particle surface. The final microcomposite samples were prepared by a combination of the traditional PM compaction technique supplemented with a conventional sintering process of the prepared green compacts. The composition and distribution of the secondary phase formed by the spinel ferrite fibers were examined by SEM. It is demonstrated that the prepared composite material has a tight arrangement without any significant porosity, which manifest itself through superior mechanical properties (high mechanical hardness, Young modulus, and transverse rupture strength) and specific electric resistivity compared to the related composite materials including resin as the organic binder.</abstract>

The Preparation of Soft Magnetic Composites Based on FeSi and Ferrite Fibers

<abstract xmlns="http://www.w3.org/1999/xhtml"> The micromechanisms of fracture of AZ61 + 1 wt. % Al2O3 composite in the zone of superplastic deformation was analysed and quantified in this work. The specimens were tested at temperature of 200°C at different strain rates. Changing the strain rate, from 1x10-2 s-1 to 1x10-4 s-1, a significant growth of ductility was observed. At maximum value of superplasticity the fracture was transcrystalline ductile with dimples of two size categories. Based on the statistical analysis of fracture micromechanisms at the elevated temperature and strain rates of 10-0- 1x10-4 s-1 hyperbolic dependency was depicted according to Gurland - Plateau theory.</abstract>

Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice,

Institute of Materials, Faculty of Metallurgy, Technical University in Košice, Park Komenského 11, 042 00 Košice,

National Taiwan University of Science and Technology, Department of Mechanical Engineering, 43, Sec.4, Keelung Rd., Taipei, 106,

Micromechanisms of Fracture of Magnesium Based Composite After Superplastic Deformation

AHEAD OF PRINT

Volume 22 (2022): Issue 1 (December 2022)

Volume 21 (2021): Issue 2 (December 2021)

Volume 21 (2021): Issue 1 (June 2021)

Volume 20 (2020): Issue 2 (December 2020)

Volume 20 (2020): Issue 1 (June 2020)

Volume 19 (2019): Issue 2 (December 2019)

Volume 19 (2019): Issue 1 (September 2019)

Volume 18 (2018): Issue 2 (November 2018)

Volume 18 (2018): Issue 1 (June 2018)

Volume 17 (2017): Issue 2 (December 2017)

Volume 17 (2017): Issue 1 (December 2017)

Volume 16 (2016): Issue 2 (December 2016)

Volume 16 (2016): Issue 1 (October 2016)

Powder Metallurgy Progress

 POWDER METALLURGY PROGRESS – international journal of powder technology and powder-derived materials.  POWDER METALLURGY PROGRESS is an international peer-reviewed open-access materials science journal with a more than 20 years long publishing history. Since the establishment in 2001, PMP published a wide variety of quality works, focused mainly on powder metallurgy of metals, the evolution of the technology itself, preparation, properties, and applications of particular materials.  In 2021 after the celebration of the 20th anniversary of the journal, it underwent changes and transformations focused mainly on the publishing interests and scope. Now it is extended to broadly all fields of powder-derived materials and technologies.  Works from the fields of powder metallurgy, metals, alloys, ceramics, and composites, basic and applied research of materials science related to mechanical and functional properties, manufacturing, and characterization are always welcomed.  Actual Scope of the journal:    materials research such as materials physics, materials chemistry, materials engineering, traditional and advanced powder metallurgy, materials processing;  wide range of metal, ceramic and composite materials including metal matrix, ceramic matrix, polymer matrix composites, and hybrid organic-inorganic-metal-ceramic material systems, structural materials, functional materials, biomaterials, porous materials, magnetic electric and multifunctional materials such as magnetic composites, magnetoelectric, magnetocaloric, ferroelectric, piezoelectric, thermoelectric, magneto-optic, magnetostrictive, or high-temperature materials;  advanced as well as traditional production technology and processing, additive manufacturing, 3D printing, Press and Sinter, HIP, MIM, PIM, Spark Plasma Sintering, Hot Pressing, Microwave Sintering, Plasma Treatment, Slip Casting, Rapid Heating, Ultrafast Sintering, new progressive compaction and processing methods;  influence of material processing parameters on their microstructure formation and development and structural relations of physical, mechanical, and functional properties of materials focusing but not limited on powder materials;  special technological processes of PM material with individual-particular-special physical-chemical properties;  environmental issues of production and application of PM materials;  industrial processes, management, and quality, (creation of normative) standard method activity, economical analysis, conception (philosophy) and prediction in PM and progressive material processing field;  production of technological equipment for powder and advanced materials technology.   The owner of the journal: Institute of Materials Research Slovak Academy of Science.  Why subscribe and read  PMP journal is an open-access journal that publishes original theoretical and experimental articles as well as review articles related to all aspects of PM. The journal is peer-reviewed, follows ethical publishing practices, and is searchable, discoverable, and citable.  Why submit  The journal has a distinguished Editorial Board with extensive academic qualifications, ensuring that the journal maintains high scientific standards and has broad international coverage. All manuscripts that are submitted to the PMP journal will NOT BE subject to any Article Processing Charges.  Rejection Rate   16.21 %   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 