Key Engineering Materials Vol. 682

Abstract: The subject of the work focuses on hardened-precipitation type alloys Al-Mg-Si which constitute the primary component material used to build homogeneous electric wires, type AAAC (All Aluminium Alloy Conductor). The material in consideration is a well-known and well-studied alloy, particularly in terms of the possibilities for using it in thermal treatment processes. However, the subject literature does not present a comprehensive recognition of the effect of heat treatment parameters on the set of mechanical and electrical properties in wires grade 6101. In particular, the study presents the results of experiments that show the possibility of controlling the AlMgSi wire properties by means of selecting the heat treatment parameters for simultaneously obtaining a high tensile strength and high electrical conductivity. Hence, the research described in this paper focuses mostly on determining the impact of the Mg and Si content on the electrical and mechanical properties of wires of Al-Mg-Si wire alloys.

Abstract: The design of a new copper alloy to obtain material characterized by the expected mechanical properties requires experiments, which enable testing the influence of different processing techniques (e.g. heat treatment operations) on the investigated material. This work consumes both time and money, and hence is a real obstacle in situations, when the researcher has limited resources for preparing and testing only a couple of copper alloy samples. The process of design and testing of a new copper alloy can be speeded up by the use of computing methods, which can be helpful especially in the prime choice of material and its processing technique. The, investigated in this work, methodologies have been chosen from the domain of Artificial Intelligence allowing for a specific nature of the experimentally obtained data, which is usually incomplete in respect of the whole knowledge concerning the studied phenomena. Application of data mining techniques (the theory of rough sets and algorithms of rules or decision trees induction) enable constructing a knowledge base as a set of rules expressing the influence of different processing techniques on mechanical properties of the tested material. Case-based reasoning (CBR), as a methodology focused on the solution of problem together with sustained learning, enables us to build an advisory system giving advice on material design and learning on experimentally obtained results. The data mining techniques and CBR methodology complement each other – the data mining techniques allow generalization of knowledge related to the performed experiments, while CBR uses knowledge in the form of individual experimental items (cases).

Abstract: This work presents the results of metallographic studies performed on four Eneolithic and Bronze Age artifacts from Poland. All of them are of none archaeological context therefore its academic value is strongly reduced. The aim of this work is to deal with such a reduced data in a way of improving and verifing current state of knowledge about the artifacts. In order to achieve this goal elemental composition (XRF), microstructure analysis (SEM-EDS), macrostructure analysis (optical microscopy) and 3D scanning were performed.

Abstract: Traditional carrying equipment that is being still used in polish railway system for dozens of years is based on typical steel profiles with low mechanical strength, low corrosion resistance and also with poor assembly and adjustment possibilities. Major part of other overhead railway equipment like support constructions, trolley wires and current carrying equipment is now modernized leaving the carrying system one of the lasts that needs to be redesigned and optimized to meet nowadays requirements for high speeds of railway travel. For that direct reason a project was started to conduct research works on design and development of the new type of railway overhead carrying equipment with enhanced exploitation properties. Within this articles authors presented a complete set of research results including designing of first concepts, FEM simulation and experimental research results including tests on final geometries in actual railway traffic. Performed studies and design works allowed to obtain an innovative overhead railway carrying system which is based on 6082 aluminum alloy and new geometry of used profiles and connection system. Research results conducted and presented within article are a part of the project co-founded by The National Centre for Research and Development.

Abstract: Protective coatings are used today in many applications for reducing friction and wear of tools in hot-working process e.g. metal die casting, hot forging, metal die plastics injection. The main goal of undertaken investigation was to evaluate usability of those coatings for improving wear resistance of metal die applied in investment casting process for wax injection. The (Ti,Al)N and (Al,Cr)N PVD coatings were deposited onto X37CrMoV5-1 hot-work tool steel and their mechanical and tribological properties are characterized in the paper. Based on the results of microscope examinations, scratch test, hardness measurement the similar properties of (Ti,Al)N and (Al,Cr)N coatings were found. Moreover it was established that type of steel surface machining before coating deposition, i.e. grinding, electrical discharge machining (EDM) and milling, did not affect coating properties. Thin coatings replicate steel base roughness parameters as Ra, Rz and Rmax with over 95% of correlation. Based on tensile test results of wax/coated steel samples and wax/uncoated steel samples the lowest wax adhesion to (Ti,Al)N coating was confirmed.

Abstract: The paper presents the results of studies of protective coatings for graphite moulds, which were used in copper casting process. The following coatings were involved: Mo, NiAl, NiCrAl, Cr₃C₂-NiCr, WC-CrC-Ni. All tested coatings were applied on the graphite substrate by plasma spraying method. The microstructure was investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The microhardness of coatings was measured by Vickers method. The wettability of coatings by liquid copper was evaluated. It was found that NiAl and NiCrAl coatings had the highest limiting wetting angle and consequently the lowest wettability among all the examined coatings. It was also found that chemical composition strongly influenced the coating properties.

Abstract: The effect of the addition of glassy carbon on the structure and properties of ZrO₂-Y₂O₂ coatings deposited at the graphite substrate has been investigated. The coatings were deposited by plasma spraying method in an industrial company Plasma System SA Silesian Siemianowice using MIM40 equipment. The microstructure of coatings was investigated by light microscopy (MO), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Abrasion was carried out with the use of tribological tester Ducom by pin-on-disc method. The results of investigations showed that the addition of the glassy carbon into coatings materials has increased microhardness and resistance against the wear.

Abstract: The present work concerns studies aiming at determination of optimal parameters of obtaining selenium coatings on a copper substrate through the cathodic reduction from sulphate and citrate solutions. The voltammetric analysis was performed in selected solutions to define electrode reactions within the examined range of potentials as well as an influence of pH on their kinetics. The range of potentials in which selenium is reduced to Se⁰, and then to Se^2- was determined. The next stage was performing several electrolysis, where the working electrode was copper. It was to define an influence of citric acid, sodium sulphate, electrolyte pH and the electrolysis potential on the quality of the obtained coatings. The coatings were analysed with the use of X-ray spectrofluorimetry, X-ray diffraction and scanning electron microscopy.

Abstract: Rapid solidification (RS) combined with plastic consolidation by hot extrusion was used to produce Al alloys with additions of varied concentration of Mn. RS flakes were manufactured using an inert gas atomizing of the molten alloy and the spray deposition on the water-cooled cooper roll. Rods of 7mm in diameter were received using cold pressing of RS-flakes, vacuum degassing and hot extrusion procedures. Mechanical properties of as extruded materials were tested in hot compression at temperature range 293K - 773K. It was found that the flow stress was reduced monotonically with deformation temperature for all tested materials. RS alloys exhibit higher mechanical properties than those produced by conventional metallurgy methods. Higher mechanical properties of RS materials are ascribed to beneficial particles morphology obtained due to the rapid solidification. Development of fine Al₆Mn particles was observed in all tested RS-materials.

Abstract: Integrated continuous casting processes are an important element of the production process in modern industry. Requirements for quality and exploitation properties of products obtained using continuous casting processes necessitate a revision of the role of impurities distribution in the material. This paper concerns on the influence of the casting process on the distribution of alloy additions. Spectroscopy studies were performed for the most sensitive elements, from the segregation, (i.e. : iron and silicon) point of view. Next obtained research results were correlated with the parameters of chemical composition such as casting speed, the presence of a modifier and the processing of metal crystallization zone. Analysis of the results clearly shows the presence of iron and silicon normal macrosegregation. It was observed that the concentration of these elements is highest in the casting axis and, in the case of iron, is 50% higher in the axis than in the circumference of casts.