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1

The structure of clusters in liquid alloys of pseudo-binary PbTe-Bi2Te3 system

Korolyshyn A. V., Olyinyk Z. M., Mudry S. I.

Archives of Materials Science and Engineering

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2019

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Vol. 100, nr 1/2

5--12

EN

Purpose: of this paper is to study the structure of melts of quasi-binary system Bi2Te3-PbTe by means of X-ray diffraction method. The aim of the research was to investigate the short range order in melts comparing it with the structure in solid state. Design/methodology/approach: Analysis of the structural factors, radial distribution functions of atoms and basic structural parameters showed that the structure of melts at temperatures near the liquidus shows microheterogeneity. Findings: On the basis of the analysis of structural factors, functions of the radial distribution of atoms and basic structural parameters, it is shown that in the given concentration the short range order structure of liquid alloys of pseudo-binary PbTe-Bi2Te3 system is microinhomogeneous and is characterized by the presence of associates, whose atomic arrangement is like to the structure of solid compounds, existing in this concentration range. Research limitations/implications: To complete the understanding of short-range order effect on the formation of the physical properties of Pb-Bi-Te alloys, further studies of the thermoelectric properties of these alloys in the liquid state are needed. Practical implications: The promise of the considered direction requires an experimental and theoretical study of the processes of bulk, thin film and nanostructured material. In this case, it is necessary to develop a technology for the synthesis of compounds of Pb-Bi-Te system, obtaining thin films and nanostructures using the vapour phase methods with studying the mechanisms of thermoelectric properties of the material formation and optimization of technological regimes for obtaining effective thermoelectric materials based on compounds of Pb-Te-Bi system. Originality/value: The processes of structure formation of nanosystems with given characteristics are investigated, because among numerous thermoelectric materials, bismuth telluride (Bi2Te3) and its alloys are the most important thermoelectric materials used in state-of-the-art devices near room temperature, and lead telluride (PbTe)-based alloys are extensively used in power supplies for space exploration and generators for use at medium to high temperatures.

2

Porównanie kinetyki sorpcji wodoru w stopie metalicznym LaNi5 i wielościennych nanorurkach węglowych

Pajdak A., Skoczylas N.

Przemysł Chemiczny

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2018

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T. 97, nr 6

959--962

PL

Przeprowadzono badania strukturalne (N2, 77 K) oraz sorpcyjne (H2, 313K, 0-2 MPa) w stopie LaNi5 oraz wielościennych nanorurkach węglowych MWCNT z uwzględnieniem kinetyki sorpcji. Powierzchnia właściwa (DFT) MWCNT wyniosła ok. 110 m2/g, a stopu LaNi5 (BJH) była bliska zeru. Pojemności sorpcyjne względem H2 (% mas.) dla LaNi5 były o ok. 2 rzędy wielkości większe od MWCNT. Czas osiągnięcia równowagi sorpcyjnej i charakter krzywych kinetyk sorpcji znacznie się różnił. Krzywa kinetyki LaNi5 miała kształt zbliżony do eksponencjalnego, a pierwszy etap kinetyki MWCNT zachodził niemal natychmiastowo i odpowiadał 60% całkowitej zmiany pojemności sorpcyjnej.

EN

H2 was sorbed in LaNi5 alloy and on multiwalled C nanotubes (MWCNT) at 313 K and 0-2 MPa to study the kinetics of sorption. The surface area of MWCNT was about 110 m2/g and the surface area of the alloy LaNi5 approached zero. The H2 sorption capacity of LaNi5 was 2 orders higher than those of MWCNT. The time necessary for the sorption balance and the sorption kinetic curves differed considerably in both cases. The kinetics curve of LaNi5 was almost exponential but the first part of the MWCNT kinetics occurred almost immediate and made up 60% of the total change of the sorption capacity.

3

The effect of deformation degree on the microstructure of the 6060 aluminium alloy

Koralnik M., Adamczyk-Cieślak B., Kulczyk M., Mizera J.

Archives of Materials Science and Engineering

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2017

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Vol. 85, nr 2

80--85

EN

Purpose: All results obtained in the present study allowed to analyse the changes in the microstructure and texture of the commercial 6060 aluminium alloy, after deformation process by severe plastic deformation. There were compare two deformation degree samples received by cumulative hydrostatic extrusion. Design/methodology/approach: The samples of the 6060 alloy were subjected to a onepass and three-passes extrusion process and next the age hardening. The microstructure changes were investigated by using transmission and scanning electron microscopy. To study the texture evolution the X-ray diffraction were made. Findings: The microscopic observations results presented the refinement of microstructure as a result of deformation process. The evolution of fibrous character of texture was observed. There were noted the disappearance of fibrous component <100> during subsequent deformation processes and generation the fibrous component <111> after high deformation degree. In addition, for each state, the presence of cubic texture component was recorded. Research limitations/implications: For the future research are planned to analyse changes in mechanical properties after hydrostatic extrusion combinate with age hardening of investigated materials. Originality/value: The paper focuses on the investigation of microstructure and texture evolution after modern method of plastic deformation.

4

Effect of severe plastic deformation by ECAP on corrosion behaviour of aluminium alloy AA 7075

Ilieva M., Radev R

Archives of Materials Science and Engineering

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2016

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Vol. 81, nr 2

55--61

EN

Purpose: The present study compares the corrosion behaviour of overaged AA 7075 before and after equal channel angular pressing ECAP in two media, containing chlorides, in order to answer the question how grain refinement of aluminium alloys influences their corrosion properties. Design/methodology/approach: The effect of equal channel angular pressing ECAP on corrosion behaviour of aluminium alloy AA 7075 was studied in two water solutions, containing chloride ions: 1) 0.01 M Na2SO4 with addition of 0.01%Cl-, and 2) 3g/l H2O2 and 57g/l NaCl. The changes in electrochemical characteristics, provoked by grain size refinement after equal channel angular pressing ECAP, were found using potentiodynamic polarisation. Steady state potential, corrosion potential, corrosion current density; breakdown (pitting) potential of overaged and deformed by equal channel angular pressing ECAP aluminium alloy AA 7075 were measured. Findings: In the environment with lower chloride concentration equal channel angular pressing ECAP process led to increase in pitting corrosion resistance and in the medium with higher chloride concentration - to decrease in pitting corrosion resistance. That way grain refinement does not demonstrate a uni-directional influence on corrosion resistance of AA 70775. Research limitations/implications: The results suggest the possibility for development of materials having the same chemical composition but with different corrosion resistance to different environments. Originality/value: The paper presents the corrosion behaviour of ultrafine-grained aluminium alloy AA 7075 and the influence of the chloride ions concentration in the corrosion medium on this behaviour.

5

CAMSS 2016 – a new software for a computer aided selection of engineering materials

Jasionowski R.

Archives of Materials Science and Engineering

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2016

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Vol. 80, nr 1

37--41

EN

Purpose: The main purpose of the paper is to present Computer Aided Materials Selection Software 2016 (CAMSS 2016) program, as well as to show its potential applicability as a tool for the selection of engineering materials. Design/methodology/approach: The project assumed a formation of computer database of materials properties and a system for the selection of structural materials. The software should be useful in industry, research entities and universities. Research limitations/implications: The only limitation of CAMSS 2016 software comes from a minimum screen resolution. The software properly display all information (including phase diagrams) when at least 1280x720 screen resolution is applied. Practical implications: CAMSS 2016 includes information regarding chemical composition, physical and mechanical properties (at low and elevated temperature), and required conditions for thermomechanical processing. CAMSS 2016 may be also applied to: the identification of materials based on chemical composition of physical and mechanical properties, a material selection for particular applications or a selection of proper material substitute. Originality/value: CAMSS 2016 is one of the few available computer programs joining two basic functions: engineering and educational.

6

Kinetics of corrosion on the intermetallic phase matrix FeAl in high temperature

Cebulski J., Lalik S.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 57, nr 1

7--14

EN

Purpose: Alloys on intermetallic phase matrix of iron and aluminium are considered the future materials for high-temperature applications as they are highly resistant to oxidation to temperature of 1100°C. The paper presents results of tests concerning kinetics of corrosion processes of alloy on intermetallic phase matrix FeAl type Fe40Al5CrTiB after vacuum casting and plastic treatment with the use of co-extrusion method and comparably for flameproof steel X12CrCoNi2120. Design/methodology/approach: Corrosion tests were conducted in gas environment including 0.08% SO2, 0.02% HCl, 9% O2 and nitrogen in temperature from 900°C to 1100°C in time of 100 hours. Kinetics of corrosion processes was marked, the condition of the surface of samples after tests was characterized with the use of electron scanning microscope and also the chemical composition of corrosion products was determined. Findings: It was stated, on the basis of tests results that the increase of weight of corrosion products in time function has a parabolic character, where the highest mass was weighed for samples after test conducted in temperature of 1100°C. A significantly higher corrosive resistance of alloys was found in comparison with the resistance of flameproof steel types CrNi with austenitic structure. Practical implications: The last feature is the reason to conduct the research for this group of materials as corrosion resistance materials. Especially FeAl intermetallic phase based alloys are objects of research in Poland and around the world in recent years. Originality/value: The aim of this paper was to determine the influence of passivation in gas environment including 0.08% SO2, 0.02% HCl, 9% O2 and nitrogen in temperature from 900°C to 1100°C in time of 100 hours on corrosion resistance of Fe40Al5CrTiB intermetallic phase based alloy.

7

The mathematical model of the mean flow stress for MgAl3Zn1Mn magnesium alloy

Cizek L., Legerski M., Rusz S., Tański T., Hadasik E., Salajka M.

Archives of Materials Science and Engineering

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2013

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Vol. 61, nr 1

5--12

EN

Purpose: The presented paper deals with method for determination of mean flow stress (MFS) which contributes to better knowledge of forming processes of hot formed magnesium alloys. Design/methodology/approach: An experiment leading to obtaining the model of the mean flow stress (MFS) of magnesium alloy AZ31 was realized in laboratory rolling mill. It resulted from mathematical and statistical processing of MFS values that these could be described by a simple function of just two independent variables – temperature (200 to 450°C) and equivalent height strain (approx. 0.2 to 0.7). The methods of the light microscopy for metallographic analyses were used. Findings: The increasing strain resulted in decreasing deformation resistance. The effect of equivalent strain rate (approx. 10-80 1/s) was negligible. The model describes the given relationship with good accuracy; a relative error of calculated MFS values does not exceed ±10%. Research limitations/implications: In future work an important relation between the MFS, the Zener-Hollomon parameter and the grain size will be determined. A significant influence of the deformation temperature on the average grain size after recrystallization was identified, while observing lower sensitivity of this parameter to an increased strain rate. Practical implications: The results of structural studies along with the devised thermomechanical model will be used to design the foundations of rolling technology for this group of alloys. The results of this paper are determined for research workers deal by development new exploitations of magnesium alloys. Originality/value: These results describe complex evaluation of properties magnesium alloys namely for determination of the values of mean flow stress (MFS) which contributes to better knowledge of forming processes of hot formed magnesium alloys and explain the structure developed used magnesium alloys after forming.

8

Copper, brass and bronze strips with controlled properties by RCS method

Głuchowski W., Domagała-Dubiel J., Sobota J., Stobrawa J., Rdzawski Z.

Archives of Materials Science and Engineering

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2013

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Vol. 60, nr 2

53--63

EN

Purpose: A growing trend to use the copper-based strips is observed recently world-wide in the electric and electronic industry . Ultrafine grained copper and solid solution hardened copper alloys are applied where high electrical conductivity and good mechanical properties are required. Design/methodology/approach: This study was aimed to investigate microstructure in strips of copper alloys with different stacking fault energy value. The investigated materials have been processed by one of the severe plastic deformation method, using different variants of continuous repetitive corrugation and straightening (CRCS). Deformation was executed by parallel and perpendicular corrugation and straightening of strip sample. Findings: Continuous repetitive corrugation and straightening is a promising method for refining of microstructure of metallic strips. Practical implications: A growing trend to use copper brass and bronze strips with improved functional properties is observed recently world-wide. Within this group of materials particular attention is drawn to those with ultra fine or nanometric grain size. Originality/value: The paper contributes to the microstructure evolution of solid solution hardened and age-hardened copper alloys strips produced by original RCS method.

9

The influence of age hardening on the microstructure of GA8 magnesium alloy

Kiełbus A., Adamiec J., Cwajna J., Paśko J.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 9

533-540

EN

Purpose: GA8 magnesium alloy is a general purpose gravity sand casting alloy containing aluminum, zinc and manganese. Typically, it is used in aerospace, automotive or commercial casting applications particularly where there is no high temperature requirement. Particularly for elements of the car interior, car body, chassis and driving gears. The aim of this paper is to present the results of investigations on the microstructure of the GA8 magnesium alloy after precipitation hardening. Design/methodology/approach: The study was conducted on GA8 magnesium alloys in as-cast condition and after heat treatment. The microstructure was characterized by optical microscopy (Olympus GX-70) and a scanning electron microscopy (Hitachi S3400) equipped with an electron dispersive detector EDS (VOYAGER of NORAN INSTRUMENTS). To measure the stereological parameters, an image analysis program "AnalysisPro" was used. Findings: A cast of the GA8 magnesium alloy shows the presence of continuous and discontinuous precipitates of ß (Mg17Al12) phase at the solid-solution grain boundaries, Moreover, the occurrence of Mg2Si and Mn5Al8 phases has been provided. After solution treatment at 415°C the area fraction of continuous and discontinuous β phase precipitates decreased. After ageing at 170°C GA8 alloy is characterized by discontinuous β phase along the solid solution grain boundaries. Area fraction of this phase increased compared to supersaturated state. Research limitations/implications: Future researches should involve investigations of the influence of precipitation hardening parameters on the mechanical properties of GA8 magnesium alloy. Practical implications: The established precipitation hardening parameters can be useful for preparing heat treatment technology of the GA8 magnesium alloy. Originality/value: The relationship between the as cast structure, precipitation hardening parameters and Mg17Al12 phase morphology in GA8 magnesium alloy was specified.

10

The effect of alloy powder morphology on microstructural evolution of hot worked P/M FeAl

Śleboda T., Doniec K.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 10

613-616

EN

Purpose: This paper presents the results of the research focused on the influence of both the starting FeAl alloy powder particle characteristics and the thermomechanical processing parameters on the microstructural evolution of these materials. Design/methodology/approach: Fully-dense FeAl alloy powder compacts were tested in compression on servohydraulic Gleeble testing machine, at the temperature range of 700*C to 1100*C, and at strain rates of 0.1 s -1 and 10 s -1. After processing, the microstructure of each deformed specimen was examined using optical microscopy. Findings: Considerable strain rate sensitivity of the investigated alloy was observed, especially with reference to microstructural development. The use of alloy powders in thermomechanical processing of FeAl alloys can substantially enhance the possibility to control both the microstructure and mechanical behavior of these alloys. Research limitations/implications: The influence of starting FeAl alloy powder particle morphology and processing strain rate on the microstructural evolution of investigated alloy was discussed. Practical implications: The results of this research could be directly employed in the design of deformation schedules for the industrial processing of FeAl alloys. Originality/value: FeAl alloy powder morphology influences the thermomechanical processing of P/M FeAl alloys, what was proved in this paper.

11

Surface modification and corrosion behavior of Ni-Ti alloy used for urological implants

Kajzer W., Kaczmarek M., Krauze A., Marciniak J.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 9

525-532

EN

Purpose: The work presents the influence of the surface treatment of Ni-Ti alloy, intended for implants applied in urogenital surgery, on their corrosion resistance. The tests were carried out in the simulated urine. In particular, the pitting and crevice corrosion resistance tests were carried out. Design/methodology/approach: The corrosion tests were realized by recording of anodic polarization curves with the use of the potentiodynamic method. The VoltaLab PGP 201 system for electrochemical tests was applied. The tests were carried out in electrolyte simulating urine (pH =5,6 ÷ 6,4) at the temperature of 37 ± 1°C. The tests were carried out on samples of the following surfaces: grinded-average roughness Ra=0,16 µm and electropolished and chemically passivated average roughness Ra=0,10 µm. Findings: Surface condition of Ni-Ti alloys determines its corrosion resistance. Research limitations/implications: The obtained results are the basis for the optimization of physicochemical properties of the Ni-Ti alloy. Practical implications: On the basis of the obtained results it can be stated that Ni-Ti alloy can be applied in urology. Originality/value: The paper presents the influence of the surface treatment on corrosion resistance of Ni-Ti alloy.

12

Influence of bone union electrostimulation on corrosion of bone stabilizer in rabbits

Szewczenko J.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 5

277-280

EN

Purpose: The aim of the work was determination of influence of the selected methods and parameters of bone union electrostimulation on corrosion of stainless steel implants coated with passive and passive-carbon layer. Design/methodology/approach: The semi-invasive and capacitively coupled electrical field methods of electrostimulation (without constant component) in rabbits were applied. The influence of electrostimulation on corrosion of implants was evaluated on the basis of the mass measurements and surface observations. Findings: On the basis of the research no corrosion on the implants stabilizing the bone fracture was observed. Research limitations/implications: Lack of visible and measurable corrosion requires the change of the methodology. Further research should be focused on the amount of metallic ions dissolved from the implants. Furthermore, it should be emphasized that the absence of corrosion of the electrostimulated implants is only one of many criteria describing the usefulness of electrostimulation parameters. The basic criterion is the biological effect obtained as the result of the electrostimulation. Practical implications: The obtained results are the basis for selection of methods and current parameters of the bone union electrostimulation in further clinical research. In case of positive results, the bone union electrostimulation with the use of implants coated with the passive and passive-carbon layers would be valuable method in treatment of pathological bone fractures. Originality/value: The paper is a continuation of the research on determining safe parameters of bone union electrostimulation of implants coated with the passive and passive-carbon layers.

13

Corrosion resistance of titanium in water solution of hydrochloric acid

Lalik S., Cebulski J., Michalik R.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 6

349-352

EN

Purpose: Most of conducted research in the area of titanium corrosion are concentrated on determine the corrosion resistance in water solution of hydrochloric acid medium at high temperatures. Recognizing of corrosion mechanisms in liquid mediums can lead to obtain corrosion-proof material e.g. by applying passivation phenomenon. In this paper attention was paid to determine the corrosion resistance of titanium in corrosive medium of liquid hydrochloric acid with concentration of 6 and 10%. Research of material susceptibility to surface activation in the pipeline of corrosion processes are conducted. Design/methodology/approach: In the corrosion tests electrolyser, potentiostat "Solartron 1285" and computer with "CorrWare 2" software were used. Results of the research were worked out with "CorrView" software. The potentials values were determined in relation to normal hydrogen electrode (NEW). The temperature of the solutions was kept at 20 °C and 50 °C. The recording of potential/density of current-time curve was conducted for 300 s. Findings: The results of research, which were conducted in 6% and 10% HCl solution, show good corrosion resistance of titanium Gr1 in temperature 20 °C. Tested samples were characterized by susceptibility to surface self-passivation, with the exception of samples tested at temperature of 50 °C in HCl water solution. Damages of titanium passive surface during exploitation can lead to short-lived increase of corrosion rate in higher temperatures. Practical implications: Results of corrosion research allow to determine the durability of titanium in 6% and 10% water solution of hydrochloric acid at temperature 20 °C and 50 °C. Originality/value: The goal of this work was to on corrosion resistance of titanium in 6% and 10% HCl water solutions.

14

Odporność korozyjna stopów metalicznych na bazie kobaltu w obecności płynu ustrojowego

Hajduga M., Kalukin A., Kalukin B.

Aktualne Problemy Biomechaniki

|

2007

|

z. 1

39--44

PL

Lokalizacja w organizmie ludzkim metali i ich stopów, może wiązać się z inicjacją zjawisk korozyjnych. W przypadku konieczności zastosowania różnych materiałów metalicznych, ich skład chemiczny powinien być zbliżony. Z uwagi na fakt, iż materiały metaliczne są poddawane przeróbce termicznej - odlewaniu, potencjały generowane pomiędzy nimi mogą się zmieniać. Celem pracy jest określenie sposobu doboru stopów protetycznych, minimalizującego możliwość wystąpienia zjawisk korozyjnych. Zakres pracy obejmuje przeprowadzenie badań: - pomiary SEM materiałów w stanie dostawy oraz odlewów - badania metalograficzne materiałów po przeprowadzeniu pomiarów SEM

EN

The placing of metals and their alloys in the human body may initiate corrosion. If it is necessary to use various metallic materials, their chemical composition should be similar. Due to the fact that metallic materials undergo thermal processing (casting), the potentials generated between them can change. The aim of this work is to determine the manner of choice of prosthetic alloys minimizing possible corrosion effects. The range of work includes the following research: - measuring electromotive force in the delivery state and casting - metallographic study of materials after measuring electromotive force

15

Production of cellular A2011 alloy from semi-solid state

Robert M. H., Delbin D.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

137--140

EN

Purpose: The work investigates a new method to produce cellular A2011 alloy and analyses the influence of processing parameters on the quality of the product. Design/methodology/approach: The proposed process involves pressing the alloy in the thixotropic semi solid state into a layer of space holder particles, which are removed after the forming operation. It is investigated the influence of the thixoforming temperature and the size of space holder particles, in the ability of penetration of the slurry in the porous pre-form as well as the structure of the obtained porous material. Products were analyzed by tomography and metallographic techniques. Findings: The proposed process showed to be able to produce acceptable porous material in a simple and low cost technique; the cellular material produced was characterized as sponge, as presented open and interconnected porosity. The quality of the product depends rather on the processing temperature than on the size of space holder particles. Low liquid fraction in the thixotropic slurry can lead to incomplete infiltration and deformation of the pre-form. In the analyzed conditions influence of the size of space holder particles could be observed neither in the processing ability nor in the quality of the product. Density of produced porous material increases as processing temperature increases, due to the increase of cells walls thickness. Research limitations/implications: The investigated process is suitable only for alloys with a significant solidification range. Practical implications: The new method to produce cellular metals can represent energy savings and is highly operational when compared to conventional methods based on liquid infiltration, since lower temperatures are involved and no need of liquid handling is required. Originality/value: The process proposed is a new one; no techniques based on thixoforming of the alloy into porous pre-forms are known so far.