<abstract xmlns="http://www.w3.org/1999/xhtml">In order to be cost effective and to meet increasing performance demands, powder metallurgy steel components require continuous improvement in terms of materials and process development. This study demonstrates the feasibility of manufacturing structural components using two different alloys systems, i.e. lean Cr-prealloyed and diffusion bonded water atomised powders with different processing conditions. The components were sintered at two different temperatures, i.e. 1120 and 1250 °C for 30 minutes in three different atmospheres: vacuum, N2- 10%H2 atmosphere as well as lean N2-5%H2-0.5%CO-(0.1-0.4)%CH4 sintering atmosphere. Components after sintering were further processed by either low pressure carburizing, sinterhardening or case hardening. All trials were performed in the industrial furnaces to simulate the actual production of the components. Microstructure, fractography, apparent and micro hardness analyses were performed close to the surface and in the middle of the sample to characterize the degree of sintering (temperature and atmosphere) and the effect of heat treatment. In all cases, components possess mostly martensitic microstructure with a few bainitic regions. The fracture surface shows well developed sinter necks. Inter- and trans-granular ductile and cleavage fracture modes are dominant and their fraction is determined by the alloy and processing route.</abstract>

Department of Industrial and Materials Science

Effect of Alloying Type and Lean Sintering Atmosphere on the Performance of PM Components

<abstract xmlns="http://www.w3.org/1999/xhtml">The effect of ball milling powder mixtures of Höganäs pre-alloyed iron Astaloy CrM, low-carbon ferromanganese Elkem, elemental electrolytic Cu and C-UF graphite on the sintered structure and mechanical properties was evaluated. The mixing was conducted using Turbula mixer for 30 minutes and CDI-EM60 frequency inverter for 1 and 2 hours. Milling was performed on 150 g mixtures with (in weight %) CrM + 1% Mn, CrM + 2% Mn, CrM + 1% Mn + 1% Cu and CrM + 2% Mn + 1% Cu, all with 0.6%C. The green compacts were single pressed at 660 MPa according to PN-EN ISO 2740. Sintering was carried out in a laboratory horizontal furnace Carbolite STF 15/450 at 1250°C for 60 minutes in 5%H2 – 95%N2 atmosphere with a heating rate of 75°C/min, followed by sintering hardening at 60°C/min cooling rate. All the steels were characterized by martensitic structures. Mechanical testing revealed that steels based on milled powders have slightly higher mechanical properties compared to those only mixed and sintered. The best combination of mechanical properties, for ball milled CrM + 1% Mn + 1% Cu was UTS 1046 MPa, TRS 1336 MPa and A 1.94%.</abstract>

The Effect of Powder Ball Milling on the Microstructure and Mechanical Properties of Sintered Fe-Cr-Mo-Mn-(Cu) Steel

<abstract xmlns="http://www.w3.org/1999/xhtml">The aim of the study was to investigate Spark Plasma Sintering (SPS) of 1-3%Mn steels and compare the resultant microstructures, strengths and failure mechanisms with those of conventionally sintered materials. SPS was performed in a vacuum of 5 Pa at 1000°C for 15min under a uniaxial pressure of 20 MPa. The heating rate of 100°C/min was applied. For conventional processing, mixtures of powders were prepared in a Turbula mixer for 30 minutes. Samples were single pressed at 660 MPa, according to PN-EN ISO 2740 standard. Sintering of compacts was carried out in a laboratory tube furnace at 1120°C and 1250°C for 60 minutes in a mixture of 95%N2-5%H2. Heating and cooling rates were 75C°/min and 60°C/min, respectively. The density of SPS samples was higher (up to 7.37 g/cm3) than those after conventional sintering (up to 6.7 g/cm3). Yield strengths of SPS samples were in the range 920-1220 MPa, compared to the maximum of 602 MPa for conventionally sintered Fe-3%Mn-0.8%C. Transverse rupture strengths were the same for this alloy, 1234 MPa, but reached 1473 MPa for SPS 2Mn variant. Interfaces in SPS samples were significantly less contaminated with oxides, which is the result of a more favorable microclimate and pressure acting during SPS. These preliminary results indicate that further research on the SPS of Mn steels is warranted.</abstract>

Faculty of Metals Engineering and Industrial Computer Science

Institute of Materials Research, Slovak Academy of Sciences

Density, Microstructure, Strength and Fractography of Spark Plasma and Conventionally Sintered Mn Steels

<abstract xmlns="http://www.w3.org/1999/xhtml">The effect of heat treatment on density, hardness, microstructure and tensile properties of Fe-0.85Mo-1.3Mn-0.6C sintered steel were investigated. Pre-alloyed Astaloy 85Mo, ferromanganese and UF4 graphite powders were mixed for 60 minutes in a Turbula mixer and then pressed in single-action die at 660MPa to produce green compacts (according to PN EN ISO 2740).The compacts were sintered in a specially designed semi-closed container at 1120 or 1250°C for 60 minutes in N2. The chemical composition of the sintering atmosphere was modified by adding getter and/or activator into the container. Two different types of heat treatment in nitrogen were carried out: sinteraustempering at 525°C for 60 minutes; and sinterhardening with additional tempering at 200°C for 60 minutes. The slightly better combination of strength and plasticity of steel for both sintering temperatures were achieved after sinterhardening+tempering variant. Average values of 0.2% offset yield stress, ultimate tensile strength and elongation after sintering in 1250°C, were 415MPa, 700MPa, and 2.0%, respectively.</abstract>

The Effects of Post-Sintering Treatments on Microstructure and Mechanical Properties of Mn-Mo Steel

<abstract xmlns="http://www.w3.org/1999/xhtml">Elemental iron and manganese powders were blended to form mixtures containing 25, 30 and 35wt.% Mn. Mixtures were compressed into prismatic bars and sintered. Some of the bars were repressed and resintered. Compared to a bar pressed and sintered once, the bar pressed and sintered twice possessed a higher relative density, a higher bending stiffness, and a grid microindentation data set with a lower variance. Bars were immersed in Hank's solution for eight weeks. After this procedure, the bending stiffness were found reduced for all bars except for those pressed, sintered and only repressed, the bending stiffness of which remained unchanged. The repressing has most likely closed up throats connecting the clusters of pores with the free surface of a bar, reducing thus a surface area exposed to a corrosive attack. The resintering has opened up those throats, the electrolyte could fill accessible pores and corrosion weakened the near-surface material, reducing thus a bar's bending stiffness.</abstract>

Microstructure, Mechanical Properties and Corrosion Behaviour of Iron - Manganese PM Materials Pressed and Sintered Once and Twice

<abstract xmlns="http://www.w3.org/1999/xhtml">The development of the nanostructure in commercial pure copper and the strength and ductility after severe plastic deformation (SPD) with the technology of equal channel angular pressing (ECAP) are analysed. Experimental results and analyses showed that both strength and ductility can be increased simultaneously by SPD. The final grain size decreased from the initial 50μm by SPD to 100-300 nm after 10 passes. An increase of the ductility together with an increase of strength caused by SPD are explained by a strong grain refinement and by a dynamic equilibrium of weakening and strengthening, and it is visible on the final static tensile test stress-strain charts.</abstract>

Institute of Materials Research of Slovak Academy of Sciences

Faculty of Materials, Metallurgy and Recycling, Institute of Materials and Quality Engineering

Mechanical Properties of Copper Processed by Equal Channel Angular Pressing

AHEAD OF PRINT

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

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

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

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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. 