Papers by Zbigniew Rdzawski
Cast zinc alloys have similar properties to aluminium alloys. The differences are due to the lowe... more Cast zinc alloys have similar properties to aluminium alloys. The differences are due to the lower melting point and higher density. Zinc has a density of 7.14 g/cm 3 , a melting point of 419.5 °C and the boiling temperature of 906 o C. In the temperature range from 150 to 200 °C, zinc has good susceptibility to plastic deformation. It is also resistant to atmospheric factor influence, but is not resistant to acids. The main use of zinc alloy, is the production of thin-walled casts that require high precision. Zinc alloys are also used for die casting moulds, housings and covers as well as a variety of devices that are used in the precision industry, electrical engineering, automotive and construction industry. Properly performed chemical modification leads to improve of properties of the produced castings. Therefore it is very important to know how the cast structure with the change of the chemical composition by adding metallic modifiers to the liquid metal. In this work there was studied the effect of chemical modification of cast zinc alloy on the properties and microstructure of the alloys before and after modification. Modified alloys were prepared by adding modifiers in the range of 0.1% to 1% in form of Ti- Sr and B as aluminium master alloy and then cast into the metal moulds. Next the thermo-derivative analysis was performed of the modified Zn-Al-Cu alloy, the microstructure investigation was carried out using light microscopy and scanning electron microscopy with EDS X-ray microanalysis usage as well as hardness was measured of the modified Zn-Al-C alloys.
... Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland * Corresponding author: E-mail addres... more ... Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland * Corresponding author: E-mail address: [email protected] Received 10.07.2008; published in revised form 01.11.2008 Analysis and modelling AbstrAct Purpose ...
2010 Proceedings of the 56th IEEE Holm Conference on Electrical Contacts, 2010
The paper outlines the manufacturing technology of different silver-metal and silver-metal oxide ... more The paper outlines the manufacturing technology of different silver-metal and silver-metal oxide composite materials to be used in contacts of low-voltage switches. There were conducted tests of the electrical properties of contacts made of eight different composite materials and hard silver. There was determined their resistance to arc erosion and static welding. There were also measured changes of contact resistance
The new high strength high electrical conductivity materials are demanded for advanced electric a... more The new high strength high electrical conductivity materials are demanded for advanced electric applications. Among them Cu-Ag and Cu-Nb wires are promising materials for generators of strong and variable magnetic fields production. Review of selected results of the studies into Cu-Ag and Cu-Nb based composite materials shows presence of various, not always well explained, mechanisms and phenomena which are observed during their production, examination and applications. Two classical copper alloys (with silver and with niobium) were selected for the investigations. The third material used in the studies was produced by bundle drawing of niobium wire in copper tube without classical melting and casting. Microstructure, mechanical and electrical properties were presented in relation to processing technology.
Journal of achievements in materials and manufacturing engineering, 2011
Purpose: The properties and the microstructure of cold drown Cu-Nb composites have been investiga... more Purpose: The properties and the microstructure of cold drown Cu-Nb composites have been investigated for their potential use as conductors in high field magnets. Nowadays, there is much activity in the development of such conductors all over the world. Design/methodology/approach: This study was aimed to investigate microstructure, mechanical and electrical properties of Cu-Nb15 wires. The investigated materials have been processed by vacuum furnace melting and casting, further hot forging and cold drawing. Alternatively material has been processed by one of the SPD (severe plastic deformation) method using oscillatory turning die pressing. Microstructure has been observed by optical and electron microscopy technics. Findings: The ultimate tensile strength versus cold deformation degree have been presented. These changes have been discussed in relation to the microstructure evolution. Practical implications: The obtained mechanical and electrical properties (UTS over 900 MPa and ele...
Archives of Metallurgy and Materials, 2016
This paper presents the research results of CuSn6 alloy strip at semi-hard state, plastically def... more This paper presents the research results of CuSn6 alloy strip at semi-hard state, plastically deformed in the process of repetitive corrugation. The influence of process parameters on the mechanical properties and structure of examined alloy were investigated. Examination in high-resolution transmission electron microscopy (HRTEM) confirmed the impact of the repetitive corrugation to obtain the nano-scale structures. It has been found, that the application of repetitive corrugation increases the tensile strength (R
Materials
The work examines the effect of rhenium addition on the structure and properties of Cu–2Ni–1Si al... more The work examines the effect of rhenium addition on the structure and properties of Cu–2Ni–1Si alloys. The aim of this work was to answer the question of how the addition of rhenium will affect the strengthening mechanisms of rhenium-modified, saturated, plastically deformed and aged Cu–2Ni–1Si alloys. How will this affect the crystallization process? What effect will it have on the properties? Scanning electron microscopy (SEM) and analysis of chemical composition in microareas (energy-dispersive X-ray spectroscopy, EDS), light microscopy, measurements of microhardness and conductivity of the alloys were used for the investigations. Research on chemical and phase composition were carried out with application of transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). Modification with rhenium has caused an increase in hardness as a result of precipitation of small phases with rhenium. As the effect of supersaturation, cold plastic treatment as w...
Archives of Civil and Mechanical Engineering
The research paper presents the impact of the scandium additive and various conditions of the hea... more The research paper presents the impact of the scandium additive and various conditions of the heat treatment on copper mechanical, electrical and heat resistance properties. The performed research works included manufacturing of CuSc0.15 and CuSc0.3 alloys through metallurgical synthesis with the use of induction furnace and following crystallization in graphite crucibles at ambient temperature. Additionally, a CuZr0.15 alloy was produced as a reference material for previously synthesized Cu–Sc alloys. During research, the selection of heat treatment for the produced materials was conducted in order to obtain the highest mechanical–electrical properties ratio. Materials obtained in such a way were next subjected to thermal resistance tests. Parameters of thermal resistance test included temperatures from the range of 200–700 °C and 1 h of annealing time. The research has shown that CuSc0.15 and CuSc0.3 alloys have higher heat resistance after their precipitation hardening compared t...
The aim of this work was to evaluate the ability of a continuous repetitive corrugation and strai... more The aim of this work was to evaluate the ability of a continuous repetitive corrugation and straightening (CRCS) technique in creating ultra fine grained copper-chromium strips as well as to determine their deformability, mechanical properties, deformation behaviour and microstructure evolution. Design/methodology/approach: Tests were performed with the 0.8 mm thick CuCr0.6 strips using original die set construction. The changes of mechanical properties as well as microstructure evolution versus number of deformation cycles were investigated. The microstructure was investigated using optical and electron microscopy (TEM and SEM equipped with EBSD). Findings: The obtained strengthening effects and observed microstructure changes have been discussed basing on the existing theories related to strengthening of ultra fine grained copper based materials. The CRCS process effectively reduced the grain size of a CuCr0.6 alloy strips, demonstrating the CRCS as a promising new method for producing ultra fine grained metallic strips. Research limitations/implications: Research results are limited to the initial material after annealing only. Further investigations should be aimed towards determination of CRCS sequence including deformationprecipitation-ageing influence on strengthening effect. Practical implications: A growing trend to use new copper-based functional materials is observed recently worldwide. Within this group of materials particular attention is drawn to those with ultra fine or nanometric grain size of a copper matrix, which exhibit higher mechanical properties than microcrystalline copper. Originality/value: The paper describes to the mechanical properties of precipitates strengthened ultra fine grained copper-chromium alloy strips obtained by original RCS method and to the microstructure evolution.
Archives of Civil and Mechanical Engineering
There is a growing demand for new high strength and high electrical conductivity materials for th... more There is a growing demand for new high strength and high electrical conductivity materials for the advanced electric applications. The promising materials for generators used to produce strong and variable magnetic fields are Cu–Ag and Cu–Nb wires. Two classical copper alloys were selected for this investigation. The third material used in the studies was produced by bundle drawing of niobium wire in a copper tube. Microstructure, mechanical and electrical properties were examined in relation to processing technology. Microstructure of Cu–Ag wires consisted of silver-rich bands distributed in a copper-rich matrix, whereas that of the Cu–Nb alloy wire was not homogeneous. Despite significant plastic deformation, globular particles of niobium, which do not contribute to the increase of mechanical properties, were also observed in addition to narrow bands of niobium-rich phase. Multiple drawing of Nb wire bundle in a copper jacket is a promising method for the production of Cu–Nb micro...
A growing trend to use new copper-based functional materials is observed recently world-wide. Wit... more A growing trend to use new copper-based functional materials is observed recently world-wide. Within this group of materials particular attention is drawn to those with ultrafine grain size of a copper matrix. This study was aimed to investigate mechanical properties, electrical conductivity and microstructure in strips of precipitation strengthened copper alloys processed by continuous repetitive corrugation and straightening (CRCS). Tests were performed with the copper alloy strips using original die set construction installed on tensile testing machine. The microstructure was investigated using optical and electron microscopy (TEM and SEM equipped with EBSD). Proposition of semi industrial application of this method have been also presented. The CRCS process effectively reduced the grain size of a copper alloy strips, demonstrating the CRCS as a promising new method for producing ultra fine grained metallic strips.
Purpose: The aim of this work was to investigate microstructure, mechanical properties and deform... more Purpose: The aim of this work was to investigate microstructure, mechanical properties and deformation behaviour of dispersion strengthened nanocrystalline copper produced by powder metallurgy techniques. Design/methodology/approach: Tests were performed with the Cu, Cu-tungsten carbide and Cu-yttria micro-composites containing up to 3 wt.% of a strengthening particles. The mechanical properties, initial nanocrystalline structures and their evolution during deformation processes were investigated. Findings: The obtained strengthening effect have been discussed based on the existing theories related to strengthening of nanocrystalline materials. The studies have shown the importance of "flows" existing in the consolidated materials and sintered materials such as pores or regions of poor powder particle joining which significantly deteriorate mechanical properties of micro-composites produced by powder metallurgy. Research limitations/implications: The powder metallurgy techniques make it possible to obtain copper-based bulk materials by means of milling input powders in the planetary ball, followed by compacting and sintering. Additional operations of hot extrusion are also often used. There is some threat, however, that during hightemperature processing or using these materials at elevated or high temperatures this nanometric structure may become unstable. Practical implications: A growing trend to use new copper-based functional materials is observed recently worldwide. Within this group of materials particular attention is drawn to those with nanometric grain size of a copper matrix, which exhibit higher mechanical properties than microcrystalline copper. Originality/value: The paper contributes to the mechanical properties of dispersion strengthened (with tungsten carbide and yttria) nanocrystalline copper and to the elucidation of deformation behaviour of these materials with high porosity.
AbstrAct Purpose: The aim of this work was to describe deformation behaviour of nanocrystalline c... more AbstrAct Purpose: The aim of this work was to describe deformation behaviour of nanocrystalline copper dispersionhardened with nanoparticles of tungsten carbide and yttria. Design/methodology/approach: Tests were made with the Cu, Cu-WC and Cu-Y 2 O 3 micro-composites containing up to 3 % of a hardening phase. These were obtained by powder metallurgy techniques, i.e. milling the input powders in the planetary ball mills, compacting and sintering. The mechanical properties (hardness, 0,2 YS, elongation during compression test) and microstructure were examined by the optical, scanning and transmission electron microscopy. Findings: Analysis of the initial nanocrystalline structure of these materials was made, and its evolution during deformation process was investigated with an account of the hardening effect and the changes in the mechanical and plastic properties. Results of this analysis have been discussed based on the existing theories related to hardening of nanocrystalline materials. Research limitations/implications: The powder metallurgy techniques make it possible to obtain copper-based bulk materials by means of milling input powders in the planetary ball, followed by compacting and sintering. Additional operations of hot extrusion are also often used. There is some threat, however, that during hightemperature processing or using these materials at elevated or high temperatures this nanometric structure may become unstable. The studies have shown the importance of "flows" in the consolidated materials such as pores or regions of poor powder particles joining which significantly deteriorate mechanical properties of compacted and sintered powder micro composites. Practical implications: A growing trend to use new copper-based functional materials is observed recently world-wide. Within this group of materials particular attention is drawn to those with nanometric grain size of a copper matrix, which exhibit higher mechanical properties than microcrystalline copper. Originality/value: The paper contributes to the elucidation of deformation behaviour of high-porosity nanocrystalline copper dispersion hardened with tungsten carbide and yttria.
ABSTRACT Purpose: This research was aimed to investigate the mechanism of Ni 3 Al phase precipita... more ABSTRACT Purpose: This research was aimed to investigate the mechanism of Ni 3 Al phase precipitation during longterm process of ageing Cu-Ni-Al. type alloys with particular account of the precipitates morphology changes, including the changes in their size with varying temperature and ageing time, so as to determine an effect of the elastic strain energy on these changes. Design/methodology/approach: Samples of cold-rolled strips from the CuNi16Al5 alloy were solution -treated at 900°C for 1h in argon atmosphere, water quenched and next aged at the temperatures of 450 and 550°C for up to 380 and 760 hours, respectively. Their microstructure was investigated by transmission electron microscopy. Findings: It was found that decomposition of supersaturated solid solution proceeds by nucleation and growth of the coherent precipitates of the L1 2 -Ni 3 Al phase. Their morphology changes as a result of competitive influence of an elastic strain energy, surface energy on the matrix-precipitate inter-phase boundary, and the energy of elastic interaction between precipitates. The L1 2 -Ni 3 Al precipitates nucleate as the spherical ones and grow, forming intermediate sub-structures, until they reach a cubic form with the planes parallel to the{100} planes of a matrix and take privileged positions along the <110> directions. Clear deviations from the LSW coagulation theory and its modifications, demonstrated by the slow-down of the process, have been observed. In the extreme case, growth of the precipitates can be completely stopped in some time ranges of the ageing process. Research limitations/implications: Further research should be concentrated on the precipitation kinetics within a wider range of volumetric fraction of the Ni 3 Al phase in a copper matrix. Practical implications: This effect can be used in practice to stabilise mechanical properties at elevated temperature. Originality/value: The paper contributes to better understanding of the precipitation mechanism in the alloys examined.
Fine platinum, and later its alloys with addition of 5-10% rhodium are used in the industrial nit... more Fine platinum, and later its alloys with addition of 5-10% rhodium are used in the industrial nitric acid manufacturing process. losses of the platinum catalyst have the deciding effect on cost of the manufactured nitric acid. the aim of conducted researches was to recognize the reasons of reduction of catalytic efficiency and occurrence of its excessive fragility. addition of the trace amount of yttrium and boron causes the drastic change of the size of crystallites, and in consequence of the durability of material.
Scripta Metallurgica, 1987
In previous work on Cu-Cr alloys [I~ , the relationships between some properties and heat treatme... more In previous work on Cu-Cr alloys [I~ , the relationships between some properties and heat treatment parameters have been presented. In this paper, the results of investigations on the microstructural changes in a Cu-Cr alloy, produced by various heat treatment parameters, is discussed. Special attention is paid to the problem of the inhomogeneous precipitation of chromium particles on grain boundaries. An analysis leading to an explanation of this phenomenon is performed.
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Papers by Zbigniew Rdzawski