Solid State Phenomena Vol. 197

Abstract: The paper presents a proof, which has been made by analyzing technological process of tested materials, that a set of quality characteristics of metal composite castings has to be different from the set of quality characteristics of castings produced out of traditional materials. However, some characteristics are similar for both material groups. These characteristics (pertaining to a set of quality characteristics of composite castings) that have been named as specific, have not been determined before. The set of characteristics has been determined on the basis of material and technological conditions as well as on methodology of diagnosing the castings quality. Basing on the Ishikawa diagram, weights of individual quality characteristics have been set along with values for particular material and technological causal groups, i.e. management, human impact, methods of manufacturing and material of composite castings and manufacturing workstation.

Abstract: The main goal of the study was working out the method of qualitative and quantitative analysis of the microstructure on 3D images of the polypropylene composites with Tuf (type of rock consisting volcanic ash) particles. Three types of composite were analyzed: with 10, 15 and 25% of Tuf. The standard morphological parameters were indicated that describes size, shape, and distribution of Tuf particles in the matrix. The morphological characterization of examined microstructure was compared with mechanical properties. The optimal from the point of mechanical properties composition of this composite were proposed.

Abstract: The paper presents the results of the influence of various etchants on the quantitative analysis of microstructure of Mg-Nd master alloy. The methodology of quantitative analysis of these alloys’ microstructure were also presented. Qualitative analysis were done using light and scanning electron microscopes, chemical composition was investigated using EDS method. Seven types of etchants were used. Having chosen suitable images, quantitative analysis were done using Met-Ilo program. Comparison of results showed that chosen etchants didn’t make the significant influence on the quantitative analysis results of the microstructure, despite visible dissimilarities.

Abstract: Carbide coatings have numerous industrial applications due to their high abrasion, sliding and erosion resistance. The paper presents results of an advanced statistical analysis – involving auxiliary simulation methods like smooth bootstrapping and imputing of missing data – executed on surface layer profile of modified carbide-ceramic coatings. Source data were gathered in the previous research by Radek and Bartkowiak focused on microstructure analysis (SEM Joel JSM-5400), microhardness (Vickers method), roughness (FORM TALYSURF-120L) and adhesion (CSEM REVETEST)) tests. Anti-wear coating were first deposited on carbon steel C45 from WC-Co-Al2O3 electrodes in the process of the electro-spark alloying (ESA) by the EIL-8a apparatus. In the next step the coating were laser melted using impulse mode of Nd:YAG laser (BLS 720 model). Due to significant irregularity of collected data, the special methods of smoothing and imputing were involved based on Monte-Carlo methods. The collected data set was several times randomly divided into analytical and verification sub-sets and mentioned methods were applied. The results were used to calculate descriptive statistics like average values, variances, confidence intervals and smoothed histograms of probability distributions. The validity of the proposed approach was positively verified and it significantly improved quality of the results. The smoothing and imputing of data allow to avoid numerical artifacts that may arise during the classical statistical calculations on irregular data.

Abstract: The aim of the work is estimation of usefulness of several selected etchants and image acquisition methods for revealing of microstructure of CMSX-4 nickel–based superalloy from computer-aided quantitative metallography’s point of view. The analysis was carried out on images registered using light and scanning electron microscopes. The images of the microstructure have been analyzed in γ γ’ eutectic’s investigations context, especially to estimate the eutectic quantitatively. The work contains description of experimental method for quantitative evaluation of γ γ’ eutectic present in as-cast state of the superalloy. A quantitative evaluation of γ γ’ eutectic islands in CMSX 4 superalloy is indispensable for a proper evaluation of γ’ phase precipitates. It is mainly related to coarse cellular γ’ phase precipitates present in γ γ’ eutectic islands.

Abstract: Properties of the Zn-Al-Cu alloys can be improved by partial or total replacement of the copper with silicon. The previous studies of the current authors have shown that in alloys with silicon addition its precipitates are not evenly distributed, which can lead to uneven wear of parts made of the Zn-Al-Cu alloy. The study of phenomena occurring during the crystallization of the ZnAl22Cu3Si alloy with ATD methods have shown that silicon does not form compounds and solid solutions with Zn and Al. In the examined alloy silicon is released as the primary even before the actual solidification of dendrites. It is not possible to reduce the irregular distribution of precipitates through heat treatment. Therefore it is important to assure the uniform distribution of precipitates of silicon already on the crystallization stage, e.g. by addition of rare earth elements. The purpose of this study was to determine the effect of rare earth elements on the morphology of silicon precipitates in the ZnAl22Cu3Si alloy. The investigated material were alloys containing 22 wt% Al, 3 wt % Cu and 1.5 wt% Si (Zn-remaining). The samples have been taken from the top, middle and bottom of the ingot. In order to determine the morphological characteristics of silicon precipitates a computer program: Met-Ilo developed in the Department of Materials Science, Silesian University of Technology was used. Changes of the area fraction and shape of precipitates in particular areas of the ingot were the subject of analysis in this work.

Abstract: Magnesium alloys are a part of a group of lightweight and ultra-lightweight alloys, which are important in practical use in constructions. QE22 casting magnesium alloy containing silver, rare earth elements and zirconium is characterized by creep resistance up to the temperature of 200 °C, while during a short exposure it can resist up to the temperature of 250°C. Nowadays, QE22 magnesium alloy are used for casting into sand moulds. In castings of magnesium alloys defects or inconsistencies (such as casting misruns, porosities and cracks) often appear, particularly in huge dimensional castings. Such defects are repaired with the use of padding and welding. Welded joints must ensure suitable operational properties, mainly in terms of creep, so that the repaired casting can work under the same conditions as the correct cast. The basic source of information about the cause and cracking propagation is fracture after creep test. The quantitative fractography, in particular profilomety, allows to describe the fracture and basis on it conclude the causes of destruction. In this paper quantitative procedure for assessing the fracture profile of QE22 welded joints after creep test was worked out. Base on its analysis result, it was found that creep resistant of the QE22 joints is determined by eutectic areas, therefore they must be heat treated after welding joints.

Abstract: Zn-Al-Cu alloys are characterized by advantageous set of functional quality futures: tribological, strength, corrosion. They are used as an alternative material for bronze, cast iron and aluminum alloys in bearings and as a structural material. Properties of Zn-Al-Cu can be improved by partial or total replacement of copper with silicon and addition of rare - earth elements. Previous studies of the current authors have shown a significant effect of cooling rate on the structure of the ZnAl22Cu3 alloy. The presence of pores and significant differences in porosity between samples slowly and fast cooled has been found. The aim of this study was to determine the effect of cooling conditions on the pore formation in ZnAl22Cu3 alloy. The article presents the structure of the slowly and fast cooled alloy. Structural examinations were carried out on samples taken from the top, center and bottom of the ingot. In order to determine the microstructure metallographic tests were carried out using optical microscope and electron scanning microscope. Through EDS X-ray spectrometry quantitative analysis of characteristic microareas was performed as well. In order to assess the morphological characteristics of the pore a computer program Met-Ilo developed in the Department of Materials Science, Silesian University of Technology has been used. Changes of the volume fraction and the average area on a flat cross section in particular areas of the ingot were analyzed quantitatively.

Abstract: Authors of the paper present structures of composite metallic-ceramic foams (Al11SiC) of characteristic internal composition, produced at Maritime University of Szczecin. Diversification of pore size and structure of composite walls is present. The foams are manufactured by injection of a gas into a liquid composite using a special device, which allows to realize the foam manufacturing process in a continuous manner. This device also allows to control the parameters of the foaming process, which results in possibility of influencing, among other things, the size and the size distribution of formed gas bubbles. After manufacturing foams with both homogeneous and diversified gas pores, basic mechanical properties of these foams were examined, revealing a connection with their structure. Possibilities of applied research methods, utilizing a microscope and a tomograph, were also presented. Methods using computer image analysis were selected for the structure description.

Abstract: The paper presents a model of microstructure changes elaborated for magnesium alloy type AZ31. In previous papers, the function of flow stress was defined on the basis of uniaxial hot compression tests. On the basis of marked relaxation curves and quantitative tests of structure the softening indicators were defined together with elaboration of equations which describe the changes in the grain size. Marked coefficients of equations were introduced in the code of simulation program. Calculations were conducted for given temperature values from 450 ÷ 250°C and strain rate from 0.01 to 10 s-1, which correspond with rolling temperature range of this alloy. Prepared model will allow the proper choice of parameters in hot rolling process of this alloy to achieve the assumed microstructure.