Obituary – Andrej Šalak

<abstract xmlns="http://www.w3.org/1999/xhtml">Boron has been known to activate densification during sintering of ferrous powder compacts, though with risk of embrittlement. In the present study, specimens Fe-B and Fe-C-B prepared from standard atomized iron powder with addition of ferroboron Fe-21%B were sintered in different atmospheres, and the resulting microstructures and properties were studied. It showed that the activating effect of boron is observed during sintering in argon and in hydrogen while sintering in N2 containing atmospheres results in rapid deactivation of boron, through formation of stable BN. In hydrogen atmosphere, surface deboronizing was observed to considerable depth. Ar is chemically inert, but Ar trapped inside closed pores tends to inhibit further densification. The impact energy data indicated that the embrittling effect of boron is enhanced significantly by presence of carbon. In the fracture surfaces, transgranular cleavage fracture can be observed both at very low and high impact energy values.</abstract>

The Role of the Atmosphere on Boron-Activated Sintering of Ferrous Powder Compacts

<abstract xmlns="http://www.w3.org/1999/xhtml">Carburizing increases the contact fatigue resistance of sintered steels, but the surface hardening may result the formation of surface brittle cracks due to the combined effect of high hardness and porosity. The effect of carburizing on the embrittlement of the case of a 7.3 g/cm3 1.5%Mo - 0.25%C sintered steel was studied. The phenomenon was analyzed theoretically and verified by experiments. The resistance of the carburized steel to surface brittle cracking increases with the load bearing surface and the decrease of the maximum pore size, of the surface microhardness and the friction coefficient. The theoretical analysis was implemented in a design procedure for parts subject to contact stresses.</abstract>

Surface Hardening Vs. Surface Embrittlement in Carburizing of Porous Steels

<abstract xmlns="http://www.w3.org/1999/xhtml">Increasing the application area of powder metallurgy (PM) steels for manufacturing of high-performance structural components results in material saving, reduction in energy consumption, etc. In this study, feasibility of the manufacturing of valve bridge component for heavy duty engine utilizing lean alloyed powders and novel vacuum sintering approach, followed by low pressure carburizing, is studied. Three low alloyed steel powders were processed by conventional uniaxial pressing and sintering at 1120 and 1250°C in industrial vacuum furnace. The components were tested under high cycle fatigue testing, simulating real conditions of operation. Fatigue properties did not show significant dependence on the sintering temperature and were comparable to currently used reference cast material. Fracture surfaces of broken samples were analyzed to detect crack initiations and fracture mechanisms as well as quality of sintering. Results showed preferentially ductile failure, well developed sintering necks and clean pore surfaces, indicating good sintering. Tested material in combination with novel vacuum sintering process show to be an attractive alternative for manufacturing of this type of components for heavy duty engine applications.</abstract>

Department of Industrial and Materials Science

Manufacturing of Valve Bridge Component Utilizing Lean Alloyed Powders and Vacuum Sintering

<abstract xmlns="http://www.w3.org/1999/xhtml">Understanding the effect of powder feedstock alterations during multicycle additive manufacturing on the quality of built components is crucial to meet the requirements on critical parts for aerospace engine applications. In this study, powder recycling of Alloy 718 during electron beam melting was studied to understand its influence on fracture behavior of Charpy impact test bars. High resolution scanning electron microscopy was employed for fracture surface analysis on test bars produced from virgin and recycled powder. For all investigated samples, an intergranular type of fracture, initiated by non-metallic phases and bonding defects, was typically observed in the regions close to or within the contour zone. The fracture mode in the bulk of the samples was mainly moderately ductile dimple fracture. The results show a clear correlation between powder degradation during multi-cycle powder reuse and the amount of damage relevant defects observed on the fracture surfaces. In particular, samples produced from recycled powder show a significant amount of aluminum-rich oxide defects, originating from aluminum-rich oxide particulates on the surface of the recycled powder.</abstract>

Department of Industrial and Materials Science, Division of Materials and Manufacture

Department of Engineering Science, Additive Manufacturing Group

Effect of Powder Recycling on the Fracture Behavior of Electron Beam Melted Alloy 718

<abstract xmlns="http://www.w3.org/1999/xhtml">The Sn–Ag–Cu (SAC) solders with low Ag or Cu content have been identified as promising candidates to replace the traditional Sn–Pb solder. In this study, an extensive discussion was presented on two major area of mechanical properties and microstructural investigation of SAC305 and SAC405. In this chapter, we study the composition, mechanical properties of SAC solder alloys and microstructure were examined by optical microscope and SEM and mechanical properties such as tensile tests, hardness test and density test of the lead solder alloys were explored. SAC305 and SAC405 alloys with different Ag content and constant Cu content under investigation and compare the value of SAC305 and SAC405. From this investigation, it was reported that tensile strength is increased, with an increase of Ag content and hardness and density were also increases in the same manner.</abstract>

Investigating the Microstructural and Mechanical Properties of Pure Lead-Free Soldering Materials (SAC305 &amp; SAC405)

<abstract xmlns="http://www.w3.org/1999/xhtml">The aim was to investigate the enamel health benefits of a novel toothpaste with active tetracalcium phosphate/monetite mixtures under de/remineralization cycling. The enamel de/remineralization cycling protocol was consisted of demineralization in 1% aqueous solution of citric acid at pH 3.6 with following treatment with toothpastes and soaking in remineralization storage solution. Effectiveness of toothpastes to promote remineralization was evaluated by surface microhardness measurements, enamel erosion depth, analysis of surface roughness and fluorescent optical method. The novel tetracalcium phosphate/monetite toothpaste had the same remineralization potential as commercial calcium silicate/phosphate toothpaste and significantly higher than control storage solution group (p&lt;0.05). Surface roughness was significantly lower after addition of fluorides to dentifrice (p&lt;0.05). The enamel erosion depth was significantly reduced by applying toothpastes as compared to negative control (p&lt;0.05) and did not differ from calcium silicate/phosphate toothpaste (p>0.66). The results showed that dentifrice formulations containing active tetracalcium phosphate/monetite mixture with or without fluoride addition had excellent enamel remineralization potential under de/remineralization cycling and successfully promote remineralization of enamel with daily using in the form of toothpaste.</abstract>

University of Veterinary Medicine and Pharmacy in Kosice

Enamel Remineralization Potential of Novel Dentifrice with Tetracalcium Phosphate/Monetite Powder Component

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. 