M. Krupiński

Phases and Structure Characteristics of the Near Eutectic Al-Sl-Cu Alloy Using Derivative Thermo Analysis

For determining of the micro-structural changes taking place in a near eutectic Al-Si-Cu aluminium cast alloy during heating and cooling process the UMSA device (Universal Metallurgical Simulator and Analyzer) was used. In this work the dependence between the regulated cooling speed and structure on the basis of the thermo-analysis was carried out. The thermal analysis was performed at a cooling rate in a range of 0,2 °C to 1,25 °C. The changes were examined and evaluated qualitatively by optical and electron scanning microscopy methods and the EDS microanalysis. During the investigation the formation of aluminium reach (α-Al) dendrites was revealed and also the occurrence of the α+β eutectic, the ternary eutectic α+Al2Cu+β, as well a iron and manganese containing phase was confirmed. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. The achieved results can be used for liquid metal processing in science and industry – for example foundry for developing and obtaining of a required alloy microstructure and properties influenced by a proper production conditions.

Methodology for Automatic Control of Automotive Al-Si Cast Components

Computer based classification methodology is presented in the paper for defects being developed in the Al alloys as the car engine elements are made from them produced with the vacuum casting method. Identification of defects was carried out using data acquired from digital images obtained using the X-ray defect detection methods. The developed methodology as well as the related X-ray image analysis and quality control neural networks based software were carried out to solve this problem.

Additives and thermal treatment influence on microstructure of nonferrous alloys

Although Zn alloys are a very widely used material, there is a need for investigations concerning the influence of thermal conditions on its microstructure and its properties, which makes it useful for the specific tasks it has to fulfil for mass-produced items manufactured by the metalworking industry, in the automotive industry, as well as in countless electronic components. One of the possibilities is to create finer microstructures and enhance their properties, to change their chemical composition by adding alloying additives, and inoculation using modifiers. So in this paper, investigation results are presented concerning the influence of chosen alloying additives, such as Sr, Ce and Ti–B on the measured and calculated thermal characteristics and microstructure of zinc alloys with the addition of aluminium and copper. Based on the results on the phase and chemical composition of the cast Zn–Al–Cu alloys, inoculated with Sr and Ti–B, no differences were detected in the phase composition of the investigated alloys, owing to changes in cooling rates, which were chosen for the sample cooling process. A small amount of added cerium caused the occurrence of new phases present in the microstructure. Modification of the Zn–Al–Cu alloy precipitates changes in the thermomorphology of the phase and the ‘tweed’ type changes in the microstructure. Moreover, the addition of cerium causes a decrease in the temperature at the beginning (TL) and the end of the solidification, as well as the occurrence of a multicomponent eutectic, which can be detected on the derivative curve.

The use of neural networks for the classification of casting defect

Employment of the artificial intelligence tools for development of the methodology of assessing quality and structural defects in Al and Mg alloys and custom-made computer software will make it possible to determine the quality of manufactured element based on digital images registered in the X-ray flaw detection examinations. The possibility to correlate the frequency and morphology of defects with the technological process parameters will make it also possible to identify and classify these defects and control the process to minimise and eliminate them. The methodology is presented in this paper, making it possible to determine the types and classes of defects developed during casting elements from aluminium alloys, making use of photos obtained from the flaw detection method with X-ray radiation. [Received 10 November 2005; Accepted 9 January 2007]

Influence of Sr addition on microstructure of the hypereutectic Zn–Al–Cu alloy

The purpose of the presented work is to answer the questions: how does the addition of strontium to the Zn–8Al–1Cu alloy crystallisation kinetics influence? What will the significance of the low temperature of heat treatment, characteristic for eutectic Zn–Al alloys, have for the formation of intermetallic phases? To describe the phenomena that occur in the metal during solidification under various conditions caused by the variable cooling rate, and as a result of the application of modifiers that provide the basis for heterogeneous nucleation, it was decided to use thermal-derivative analysis method. The mentioned method allows to accurately describe and interpret the kinetics of crystallisation of the tested materials. The effectiveness of the modification was assessed based on a degree of fragmentation of the structural components and changes in the properties of the material being modified, as well as by analysis of the cooling curves of the tested alloys. The thermal events occurring during solidification process, i.e. liquidus (TL) and solidus (TSol) temperatures and the beginning of phases and eutectic nucleation, were determined with the thermal-derivative analysis and calculation of total heat of crystallisation of the analysed material.

Thermo-derivative analysis of Al–Si–Cu alloy used for surface treatment

The only effective way to design, produce, analyse and optimise new and existing industrial thermal processes and also laser-based processes is to develop a quantitative knowledge and understanding of the dependence between temperature and time, which allow the desired forming of properties of the final products. The purpose of this paper was the performance of thermo-derivative analysis using the UMSA platform of aluminium alloy cooled at chosen rate, for obtaining characteristics used later for laser treatment and its influence on the microstructure and properties of the surface layer of heat-treated Al–Si–Cu cast aluminium alloys, using the high-power diode laser. The performed laser treatment involves remelting and feeding of ceramic powder into the aluminium surface. The carried out investigations allow to conclude that as a result of alloying of the heat-treated cast aluminium alloys with oxide ceramic powder, a surface layer was obtained with higher hardness compared to non-laser-treated material. The surface layer can be enriched with the powder particle, and in some cases a high-quality top layer is possible to obtain. Also a microstructure refinement of the surface layer was achieved due to the high laser power use and consequently high cooling rate during the crystallisation process. Concerning original practical implications of this work, there was important to investigate the appliance possibility of thermal analysis for further surface treatment for enhancement of the aluminium surface properties, especially the wear resistance and hardness. The scientific reason was also to describe microstructure changes and processes occurred in the laser remelted surface aluminium layer after laser treatment.

Heat Treatment of Al-Si-Cu Alloys

The aim of the presented work is an effort to answer the research questions, i.e. how to determine the optimal supersaturation temperature for multicomponent alloys What is the relationship between changes in the derivative curve of composites and the relationship between their chemical composition and microstructure Searching for the right answer to the above questions was the basis for determining the scope and methodology of the presented work. To describe the phenomena that occur in the material during solidification under various conditions caused by the variable cooling rate and variable chemical composition it was decided to use thermal-derivative analysis methods. The mentioned method allows to accurately describe and interpret the kinetics of the crystallization of the tested materials. This method is often used in the search for new directions of modern technologies, attractive from both experimental and cognitive. This methodology allows to determine the relationship between crystallization kinetics and usable casting properties on the example of Al-Si-Cu alloys and other alloying elements.

Crystallisation kinetics and structure of modified Zn–Al–Cu alloys

The primary purpose of the work was to try to answer the following questions: How will the addition of lanthanum and cerium affect the crystallisation kinetics of the alloys tested? What will be the relationship between changes in the shape of the derivative curve and the microstructure and the same properties of Zn–Al10–Cu1 alloys? To improve properties of the casting zinc alloy, modification of the structure consisting in the change in the morphology of alloy structural constituents has been applied, primarily by reducing interfacial eutectic α′ + η, reduction in the size of fundamental components, as well as the effect of La on the change in the grain morphology of the solid solution with the aluminium matrix from the dendritic one to the “tweed” one. To describe the phenomena that occur in the material during solidification as a result of the application of modifiers, the thermal derivative analysis and structural analysis using scanning and transmission electron microscopy method were carried out.

Effect of chemical composition modification on structure and properties of the cast Zn-Al-Cu alloys

The effect of Sr, Ti-B addition on structure and properties of cast Zn-Al-Cu alloys is presented in this work. Cu as well as master alloys such as Al-Sr and Al-Ti-B were added to the zinc alloy, which was cast into a metal mould. The thermo-derivative analysis was performed using the UMSA platform (Universal Metallurgical Simulator and Analyzer) with cooling at different rates in the range from 0.09 to about 0.2 ℃ s−1. The effect was investigated of the mass concentration of alloying elements ranging from 0.1 to 1% and of the varying cooling rates on the alloys’ structure and properties, including corrosion resistance in the salt vapour environment, as well as its hardness and abrasion wear resistance in the metal-to-metal setup. Alteration of the chemical composition of the cast Zn alloys by the addition of modifiers was made to change their structure and thereby possibly improve the alloys’ properties and also the functional ones.