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1

Comparison of ultrasonic and other atomization methods in metal powder production

Bałasz B., Bielecki M., Gulbiński W., Słoboda Ł.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 116, nr 1

11--24

EN

Purpose: Additive manufacturing (AM) research needs new alloys to grow and offer new functionalities. This paper presents a novel powder production method by means of ultrasonic atomisation (UA). Powders for AM can be obtained from gas atomisation (GA) and a comparative study of UA- vs GA-made powders were carried out. To UA explain the pros & cons more clearly, a summary of the processes was added, along with the analysis of the droplet formation physics. Design/methodology/approach: Ultrasonic atomization (UA) with melting raw material by an electric arc. Characterisation of the powders: particle size distribution (PSD), density, and flowability were carried out. Other parameters, such as microstructure, deviation in the chemical composition and powder surface morphology, were also investigated. Findings: The results showed that the UA powder has a finer average particle size with a narrower statistical distribution of particles than those made by the GA method. Because the UA powder has a higher sphericity and lower porosity, Generally, UA offers better-quality powders in terms of properties such as higher tap density, better flowability and low oxygen content. Research limitations/implications: As an example of semi-industrial scale application of the UA system, the Ti6Al4V and TiAl powders were produced after remelting the wire. The UA system is commercially available for processing any metallic material. Practical implications: The test campaign results showed that the Ti6Al4V powder produced by the ultrasonic atomisation has a similar or better quality as those available from large-scale gas atomisation plants. Originality/value: The new method of UA powder production was analysed in terms of key powder parameters. The properties of the titanium-based powder produced this way were analysed with a view to future applications.

2

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.

3

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.

4

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.

5

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.

6

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.

7

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.

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 skeleton castings as a new type of cast lattice structures

Cholewa M., Szuter T., Wróbel T., Kondracki M.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 54, nr 2

250--259

EN

Purpose: of this paper is to present selected achievements in field of new type material - skeleton structures. Actual state of knowledge about periodic cellular materials was described. The aim of this work is to show results about mechanically optimised skeleton casting with octahedron topology. Correctness of technological parameters was investigated by microstructural research. Most important parameters of the manufacturing process were identified. Design/methodology/approach: The influence of technological parameters to the microstructure in different points of casting was described. Simulations of the mould filling processes were also carried out. Real experiments were performed to prove the simulation results. The qualitative and quantitative metallographic analysis was also carried out. Findings: It was found that the octahedron shape of internal cell causes best stress distribution and that the skeleton castings are a good alternative for cellular materials such as metal foams, lattice structures or sandwich panels. Research limitations/implications: Casting methods used to manufacture materials such as described skeleton castings confirmed their usefulness. Not well known and used yet rheological properties of liquid metals allow obtaining shape complicated structures near to metallic foams but with periodic structure. Practical implications: Technological parameters of the skeleton castings manufacturing process were developed. Without use of advanced techniques there is a possibility to manufacture relatively low cost skeleton structures in a typical foundry. Originality/value: Three dimensional cast skeleton structures with internal topology of octahedron confirmed their usefulness as elements used for energy dissipation. Obtaining the homogenous microstructure in the whole volume of complicated shape castings can be achieved.

10

The iron-nickel-molybdenum (Fe-Ni-Mo) electrodeposited alloy on n-type silicon

Fekih Z., Ghellai N., Sam S., Chabanne-Sari N., Gabouze N.

Advances in Materials Science

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2012

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Vol. 12, nr 1(31)

17-26

EN

In the present work, the electrodeposition of iron-nickel-molybdenum (Fe-Ni-Mo) alloy on n-type silicon (Si) is investigated. A voltamperometric study has been carried out. According to the composition of the solution and of its pH, the properties of final deposit have been investigated and analyzed by X-rays diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Under our conditions an amorphous FeNiMo alloy was formed. The morphology of deposited layer was strongly influenced by the polarization and the molybdenum dominance in the final chemical composition of the deposited film. Moreover, high percentages of molybdenum can be obtained from high molybdate concentrations and grain size increase with increasing Mo concentration. We also noticed that an absence of nickel was accomplished by applying more negative potential.

11

Thermomechanical processing of CuTi4 alloy

Rdzawski Z., Stobrawa J., Głuchowski W., Konieczny J.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

9-25

EN

Purpose: One of the reasons behind the interest in copper titanium alloys was development of new materials to substitute copper beryllium alloys. The reason for selecting that material for studies was that in the early stages of decomposition of CuTi4 alloy a spinodal transformation takes place and ordering processes begin. Proper selection of heat treatment and plastic working conditions provides possibilities to produce very wide range of sets of properties by formation of the required alloy microstructure. Therefore the main objective of the study was to capture the changes in precipitation kinetics, especially in the relations between supersaturation and ageing or between supersaturaion, cold deformation and ageing in connection to the changes in microstructure and functional properties (mainly changes in hardness and electrical conductivity). Design/methodology/approach: Melting of the charge material was conducted in medium-frequency induction furnace, in a graphite crucible. The melted material after bath preparation was poured into a cast iron ingot mould (with graphite grease applied on the inside) of dimensions 35 x 120 x 250 mm. The ingots after casting were peeled. The treated ingots were heated in resistance furnace at 900şC for 1.5 hour and rolled down on a reversible two-high mill. Findings: Decomposition of supersaturated solid solution in that alloy is similar to the alloys produced in laboratory scale. The observed differences in microstructure after supersaturation were related to the presence of undissolved Ti particles and increased segregation of titanium distribution in copper matrix including microareas of individual grains. The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the alloy. Research limitations/implications: Cold deformation (50% reduction) of the alloy after supersaturation changes the mechanism and kinetics of precipitation and provides possibilities for production of broader sets of functional properties. It is expected that widening of the cold deformation range should result in more complete characteristics of material properties, suitable for the foreseen applications. Similar effects can be expected after application of cold deformation after ageing. Practical implications: The elaborated research results present some utilitarian qualities since they can be used in development of process conditions for industrial scale production of strips from CuTi4 alloy of defined properties and operating qualities. Originality/value: The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the Cu-Ti alloys.

12

The microstructure and properties of the bainitic cast steel for scissors crossovers

Pacyna J., Bała P., Dobosz S., Kokosza A., Kąc S.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

19-26

EN

Purpose: The main purpose of the hereby study was the description of microstructure and properties of the new low-carbon Mn-Cr-Mo-V-Ni bainitic cast steel developed in the AGH Laboratory of Phase Transformations for cast mono-blocks of scissors crossovers. Investigations comprise material in as-cast state and after various variants of normalization as well as normalization and high tempering. Design/methodology/approach: Analyses of microstructure, strength properties, impact toughness and crack resistance (KIc) were performed both for material in the as-cast state and after heat treatments. The influence of the initial microstructure on the investigated cast steel hardness – after the normalizing and after the normalizing and tempering – was determined. Findings: Changes in the microstructure of the cast bainitic scissors crossovers were determined and their properties described. Research limitations/implications: The investigations were performed in order to estimate a possibility of applying bainitic cast steels for production of scissors crossovers in the form of monolithic blocks. Practical implications: Application of bainitic cast steels for scissors crossovers in the form of monolithic blocks. Originality/value: Designing of the chemical composition of the bainitic cast steel (Mn-Cr-Mo-V-Ni) and its heat treatment.

13

The influence of heat treatment on microstructure and crack resistance of boron microalloyed steel plates

Opiela M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

117-124

EN

Purpose: The work presents results of investigation of heat treatment conditions influence on microstructure and crack resistance of C-Mn constructional steels with microaddition of boron assigned to be used in production of high strength steel plates. Design/methodology/approach: Metallographic observations, heat treatment, hardness measurements, impact strength examinations, fractographic analyses of fracture surfaces of test pieces have been performed. Findings: Dispersive particles of interstitial phases formed on dislocations during the plastic deformation, limiting grain growth of austenite, create the possibility to obtain metallurgical products with fine-grained microstructure giving them high strength and guaranteed crack resistance, also at low temperature. Research limitations/implications: Further research of microstructure in transmission electron microscope as well as complementary impact resistance tests at the temperature lower than -60°C are foreseen to be performed. Practical implications: Obtained results of examinations, especially detailed fractographic analysis of fracture surfaces of test pieces together with chemical composition analysis of revealed non-metallic inclusions and precipitations of secondary phases will make contribution to better understanding of cracking mechanisms in the group of high-strength steels. Originality/value: Performed research revealed that investigated steels present high crack resistance also at low temperature. It can be achieved through proper selection of chemical composition and adequate conditions of heat treatment and plastic working. The presence of microadditions of transition metals deriving from IVb and Vb group of periodic classification of the elements with high chemical affinity to nitrogen and carbon allows producing rolled products with high exploitation properties. Keywords: Metallic alloys; Heat treatment; Microalloyed steels; Heavy plates; Crack resistance

14

Prevention methods against hydrogen degradation of steel

Ćwiek J.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

214-221

EN

Purpose: of this paper is presentation of mechanisms and forms of hydrogen degradation in steel along with pointing out methods for hydrogen degradation prevention. Design/methodology/approach: Hydrogen degradation of steel is a form of environmentally assisted failure which is caused by the action of hydrogen often in combination with residual or applied stress resulting in reduction of plasticity, load bearing capacity of a component, and cracking. Findings: The sources of hydrogen in steel were presented. Forms of hydrogen presence in metals, mechanisms of hydrogen degradation, and types of hydrogen induced damage were discussed in details. Five specific types of hydrogen induced damage to metals and alloys could be distinguished: hydrogen embrittlement, hydrogen-induced blistering, cracking from precipitation of internal hydrogen, hydrogen attack, cracking from hydride formation. Practical implications: Methods for hydrogen degradation prevention include: selection of suitable material, modifying environment to reduce hydrogen charging, and use of surface coatings and effective inhibitors. Originality/value: Originality the paper outlines the problem of hydrogen degradation of steel and other alloys, delivering knowledge to undertake preventive or remedial actions in order to avoid hydrogen induced degradation.

15

Morphological features of retained austenite in thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multiphase steel

Grajcar A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

7-18

EN

Purpose: The aim of the paper is to determine the influence of isothermal bainitic transformation temperature on morphological features and a fraction of retained austenite in a new-developed thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multiphase steel. Design/methodology/approach: The thermo-mechanical processing was realized in a multi-stage compression test by the use of the Gleeble thermomechanical simulator. The steel was isothermally held for 600 s in a bainitic transformation temperature range of 250 to 500°C. A fraction and stereological parameters of retained austenite were determined by a computer image analyser using an optical microscope. The details of the retained austenite morphology were revealed in a scanning electron microscope and using EBSD technique. Findings: The maximum fraction of retained austenite (above 14%) was obtained for the temperatures of isothermal bainitic transformation from 400 to 450°C. Below 350°C, the largest grains of retained austenite located in a ferritic matrix transform to martensite and its fraction estimated by the use of computer image analysis is too high compared to X-ray investigations. Blocky, irregular grains located in a ferritic matrix are a main structural constituent of retained austenite in a temperature range up to 350°C. Increasing the isothermal holding temperature to a range of 400-450°C results in increasing a fraction of fine blocky and layer regions of the ă phase. Research limitations/implications: To describe in detail morphological features of retained austenite in fine-grained multiphase structures, a combination of different methods characterized by various resolution is necessary. Practical implications: The revealed morphological features of retained austenite are of great importance for mechanical stability of this phase during cold straining, affecting mechanical properties of advanced TRIP-assisted steels. Originality/value: Combined colour etching, scanning electron microscopy and EBSD (Electron Backscattered Diffraction) methods were applied to characterize retained austenite in a modern group of thermomechanically processed TRIP steels with Nb and Ti microadditions.

16

Micro-forming of Al-Si foil

Haga T., Inoue K., Watari H.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 40, nr 2

115-122

EN

Purpose: of this paper is as below. The investigation of the ability of the cold micro-forming of non-metallic glass was purpose. The grain of the rapidly solidified aluminium alloy became fine. The aluminium alloy foil with fine grain was used, and the investigation of the micro-formability of this alloy was investigated. Moreover, increase of the forming speed was investigated. The increase of the forming speed was purpose of this study, too. Design/methodology/approach: The nozzle pressing melt spinning method was used to attain the rapid solidification of the non-metallic grass. The Al-14mass%Si, which is hyper eutectic but is close to eutectic, was used. The roll contact surface was formed by V-groove. The cold rolling was adopted for forming. The V-groove was machined at the roll surface. The micro-forming was operated at the cold work. Findings: Micro-forming of the crystal aluminium alloy was able by the cold work. The forming speed was 0.04S to form 10 ěm height. The forming speed could be drastically increased. Research limitations/implications: The angle of the V-groove, which was used in the present study, was only 60 degrees. The effect of the groove angle on the protrusion-height was not clear. The used material was only the Al-14mass%Si. Relationship between the material and protrusion-height was not clear. Practical implications: The die for the micro-forming of the resin could be made from economy material by the conventional cold rolling process at short time. Therefore, the mass production of the economy die for resin may be obtained. Originality/value: The micro-forming of the rapidly solidified non-metallic glass by cold work was original.

17

Investigations of microstructure and dislocations of cast magnesium alloys

Tański T., Dobrzański L. A., Labisz K.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

94-102

EN

Purpose: The microstructures and the dislocation arrangements in the cast magnesium alloy have been investigated using transmission electron microscopy and high-resolution transmission electron microscopy. In this paper are presented also the results of phase morphology investigation of an new developed Mg alloy. Such studies are of great interest for the metal industry, mainly the automobile industry, were the improvement of cast elements quality is crucial for economic and quality reason and depends mainly on properly performed controlling process of the production parameters. There are presented especially the effect of heat treatment on the size and distribution of the precipitation occurred in the matrix. Design/methodology/approach: The basic assumptions of this work are realised an Universal Metallurgical Simulator and Analyzer. The solidification process itself is analysed using the UMSA device by appliance of the Derivative Thermo Analysis. The thermal analysis was performed at a low but regulated cooling rate in a range of 0.2 oC to ca. 3 oC. Cooling curve for the thermal analysis was performed using a high sensitivity thermocouples of the K type, covered with a stainless steel sheath. The data were acquired by a high speed data acquisition system linked to a PC computer. Two different types of samples were used, bulk-cylindrical, and thin-walled cylindrical. Metallographic investigation were made on cross section samples of a engine bloc. Non-equilibrium heating and cooling process conditions were applied to achieve changes in shape and distribution of the phases such as Al2Cu and Si. Findings: During the investigation Dislocation networks are found to increase with deformation in all cases. The dislocation networks have been found in the g- Mg17Al12 phase as well as in the matrix in the investigation magnesium alloys. The crystallographic orientation relationship are: (1 01) .-Mg Ś (10 ) Mg17Al12 and [11 0] .-Mg Ś [111] Mg17Al12. Precipitation of the g-Mg17Al12 phase are mostly of the shape of roads, and the prevailing growing directions are the directions <110> .-Mg. Research limitations/implications: The investigations were performed using standard metallographic investigation as optical, scanning and transmission electron microscopy methods, also electron diffraction methods were applied for phase identification. Originality/value: The originality of this work is based on applying of regulated cooling rate of magnesium alloy for structure and mechanical properties changes. In this work the dependence between the regulated heat treatment, chemical composition and structure of the investigated magnesium cast alloy on the basis of the structure investigations was presented.

18

Image analysis used for aluminium alloy microstructure investigation

Krupiński M., Labisz K., Dobrzański L. A., Rdzawski Z.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

58-65

EN

Purpose: In this work the metallographic microstructure analysis of the investigated AlSi7Cu3Mg aluminium cast alloy was performed for samples cooled with different cooling rate settings. The preformed investigations are subjected to the analysis of cooling rate influence on the phase morphology. Design/methodology/approach: The solidification process itself is analysed using the UMSA device by appliance of the Derivative Thermo Analysis. The influence of the cooling rate on the alloy microstructure was investigated using computer aided image analysis, in this work also the content of particular phases was analysed, as well the percentage of pinholes compared to the chosen cooling rate. Findings: The treated sample is without holes, cracks and defects as well as has a slightly higher hardness value compared to the as-cast material. Research limitations/implications: The investigated samples were made of the cylindrical shape and were cooled in the range of 0.2°C/s to 1.25°C/s. In this work also the derivative thermoanalysis was performed to determine the correlation between the chosen cooling rate and the microstructure as well changes in the derivative curve shape. For alloy cooling with chosen cooling rate as well for the derivative thermo-analysis the UMSA analysator was applied. Practical implications: The investigated material can find its use in the foundry industry; an improvement of component quality depends mainly on better control over the production parameters. Originality/value: The originality of this work is based on applying of regulated cooling rate of aluminium alloy for structure and mechanical properties changes. As an effect of this study it will be possible to understand and to influence the mechanism of structure forming, refinement and nucleation. Also a better understanding of the thermal characteristics will be provided to achieve a desirable phase morphology required for application of this material under production conditions.

19

Derivative thermo-analysis application to assess the cooling rate influence on the microstructure of Al-Si alloy cast

Krupiński M., Labisz K., Dobrzański L. A., Rdzawski Z. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 2

115-122

EN

Purpose: The application of the UMSA device (Universal Metallurgical Simulator and Analyzer) has allow to determine the liquidus/solidus thermal points of solidified alloy, as well the thermal points, where phase- or eutectic crystallisation occurs. Design/methodology/approach: Investigations were performed using cast aluminium-silicon alloys, known as EN AC-4XXXX according to the PN-EN 1706:2001 standard. The solidification process was investigated using the metallurgical UMSA simulator connected to recording devices equipped with simulating cooling system. For the alloy microstructure investigation the optical microscope and transmission and scanning electron microscope with EDS equipment were used for evaluation of the chemical composition of the phases occurred in the investigated alloy. Findings: Investigation of the interdependences occurred between phase morphology and cooling rate using thermo-analysis has given the main results. Practical implications: In the metal casting industry the improvement of the quality of components depends mainly on proper control over the production parameters. Originality/value: The performed investigations allow to determine the microstructure changes as well the derivative curves in comparison to the cooling rate applied for the alloy.

20

Crystallization kinetics of Zn alloys modified with Ce, La, Sr, Ti, B

Krupińska B., Labisz K., Dobrzański L. A., Rdzawski Z.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

50-57

EN

Purpose: This paper presents the investigation results of cooling rate influence on microstructure of the Zn-Al cast alloy. Thermo-derivative analysis of the investigated alloys was performed using the UMSA device (Universal Metallurgical Simulator and Analyzer). This device makes it possible to characterise the important points of the crystallised alloy diagram including: phase and eutectics crystallisation, as well liquidus/solidus points. The material used for investigation was the ZL8 alloy. Design/methodology/approach: Moreover the analysis of cooling rate influence on the derivative curve changes was performed as a result of the measured crystallisation kinetic changes. For the assessment of the cooling rate influence on the mechanical properties also hardness measurements were performed using the Rockwell hardness device. Findings: The treated sample is without holes, cracks and defects as well as has a slightly higher hardness value compared to the as-cast material. Research limitations/implications: Microstructure and mechanical properties investigations of the investigated alloy was performed for the reason of alloying additives influence on alloy microstructure and properties change, the microstructure was analyzed qualitatively using light and scanning electron microscope as well as the area mapping and point-wise EDS microanalysis. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. Practical implications: The investigated material can find its use in the foundry industry; an improvement of component quality depends mainly on better control over the production parameters. Originality/value: This work provides better understanding of the thermal characteristics and processes occurred in the new developed alloy. The achieved results can be used for liquid metal processing in science and industry and obtaining of a required alloy microstructure and properties influenced by a proper production condition.