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Open access

B. Ertuğ, B. Nilgün Çetiner, H. Gökçe, Z. Engin Erkmen and M. Lütfi Öveçoğlu

Abstract

In the present study, mechanical properties of 0.25Li2O.2SiO2-0.75BaO.2SiO2 glass-ceramic were investigated. The trans-formations‘ temperatures were determined by DTA instrument. The optimum nucleation temperature was found to be 540°C. This suggested the crystallization temperatures as 675, 720 and 800°C. After carrying out crystallization heat treatments, Vickers indentation test was applied. In order to determine the indentation fracture toughness (KIC), crack half-length ‚c‘ of the samples was measured. To calculate KIC, Young’s modulus, E and the measured hardness, Hv were used. Using KIC and probability of fracture ‚P‘, ln ln[1/(1 − P)] – ln KIC graph was drawn based on the Weibull distribution equation. Consequently, Weibull modulus, ‚m‘ and scale parameter, ‚K 0‘ were determined and compared with each other.

Open access

D. Pasek and J. Cebulski

Abstract

The article presents the results of studies on the effects wrought on the corrosion resistance of the alloy matrix phase inter-metallic FeAl. Researches were carried out on the Fe40Al5Cr0.2TiB alloy and involved the oxidation of the samples after the crystallization after plastic deformation made by extrusion. The tests were performed in an oven in air at 1100°C for 100, 300 and 500 h. Determined to change the mass of the samples after corrosion research setting kinetics of corrosion processes, as well as an analysis of the microstructure of the alloy after the crystallization and after forming. The structure was examined using light microscopy and scanning electron microscopy and X-ray microanalysis with EDS chemical composition of the corrosion products. The test results revealed that plastic deformation during extrusion of intermetallic alloy led to structural changes, the effect of which was to improve the heat resistance at a temperature of 1100°C.

Open access

T. Ratajski, I. Kalemba-Rec and B. Dubiel

Abstract

The effect of anionic surfactant in the form of polyacrylic acid (PAA) on the electrophoretic deposition of the SiO2 and Ni/SiO2 coatings on X2CrNiMo17-12-2 stainless steel was examined. Parameters of the process, such as chemical composition of the suspensions, voltage between the electrodes and the deposition time were experimentally selected. Zeta potential measurements showed a beneficial effect of polyacrylic acid on the SiO2 and Ni particles stability in ethanol. Scanning and transmission electron microscopy studies revealed that the microstructure of the coatings obtained from the suspensions containing polyelectrolyte is more homogenous and has less amount of desiccation cracks on the surface. The results of the polarization tests have shown that addition of anionic surfactant improves also corrosion resistance of the coatings in 3.5% NaCl solution.

Open access

P. Sochacka, A. Miklaszewski and M. Jurczyk

Abstract

Titanium β-type alloys are a class of interesting biomaterials that can exhibit a unique combination of mechanical as well as physicochemical and biological properties. The aim of this study is to develop a titanium-molybdenum alloys (Ti-x at % Mo, x = 15 and 23). These materials were prepared by the combination of mechanical alloying and powder metallurgical process. The details of the processing method were presented. The samples were characterized by X-ray diffraction, scanning electron micros-copy, chemical composition determination as well as density and Vickers microhardness measurements. The corrosion behaviour in Ringer solution was investigated, too. The crystallization of the obtained material upon annealing led to the formation of a near single β type alloys. The molybdenum content in titanium and heat treatment parameters of a nearly amorphous phase allow to synthesize Ti(β)-type alloys. The present study has demonstrated that Ti23Mo alloy can be the next generation of biomaterial for bone tissue engineering.

Open access

A. Glowacz, W. Glowacz, Z. Glowacz, J. Kozik, M. Gutten, D. Korenciak, Z. F. Khan, M. Irfan and E. Carletti

Abstract

A degradation of metallurgical equipment is normal process depended on time. Some factors such as: operation process, friction, high temperature can accelerate the degradation process of metallurgical equipment. In this paper the authors analyzed three phase induction motors. These motors are common used in the metallurgy industry, for example in conveyor belt. The diagnostics of such motors is essential. An early detection of faults prevents financial loss and downtimes. The authors proposed a technique of fault diagnosis based on recognition of currents. The authors analyzed 4 states of three phase induction motor: healthy three phase induction motor, three phase induction motor with 1 faulty rotor bar, three phase induction motor with 2 faulty rotor bars, three phase induction motor with faulty ring of squirrel-cage. An analysis was carried out for original method of feature extraction called MSAF-RATIO15 (Method of Selection of Amplitudes of Frequencies – Ratio 15% of maximum of amplitude). A classification of feature vectors was performed by Bayes classifier, Linear Discriminant Analysis (LDA) and Nearest Neighbour classifier. The proposed technique of fault diagnosis can be used for protection of three phase induction motors and other rotating electrical machines. In the near future the authors will analyze other motors and faults. There is also idea to use thermal, acoustic, electrical, vibration signal together.

Open access

A. Vaško

Abstract

Three melts of ferrite-pearlitic nodular cast iron with different charge composition were used for fatigue tests. Wöhler fatigue curves and fatigue strength were obtained, and microstructure and fracture surfaces were investigated. The aim of the paper is to determine the influence of charge composition on microstructure, mechanical and fatigue properties of synthetic nodular cast irons and their micromechanisms of failure. Fatigue tests were realised at low frequency sinusoidal cyclic push-pull loading (stress ratio R = −1) at ambient temperature (T = 20 ±5°C). They were carried out with using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100 at frequency f ≈ 120 Hz. The results of fatigue tests at low frequency cyclic loading are compared with fatigue properties at high frequency cyclic loading.

Open access

S. Kut, F. Stachowicz, G. Ryzińska and T. Mrugała

Abstract

Results of experimental investigations of metal spinning process of AMS 5504 sheets. cylindrical drawpieces with use of discs-shaped sheet with various diameter and thickness were shown in this work. Tests were performed on two roller metal spinning machine of a vertical axis Leifeld SFC 800 V500.

The main objective of the study was to determine the dependence between limiting spinning coefficient, thin wall ratio coefficient and the fillet radius of forming rollers. To realize this aim required the development of an original methodology and experimental research plan. Determined relationship takes into account the occurrence of negative phenomena in the process of spinning such as wrinkling or cracking of material.

Due to the possibility of prediction of these negative phenomena, determined relationship is used in the design of a metal spinning processes. On the basis on determined relationship can be done a practical assessment of the possibility of shaping with certain geometrical parameters by spinning. Obtained results were shown graphically on the diagrams and their analysis was carried.

Open access

M. Wronski, K. Wierzbanowski, S. Wronski, B. Bacroix and P. Lipinski

Abstract

The goal of this work was theoretical and experimental study of micro- and macroscopic mechanical fields of 6061 aluminum alloy induced by the asymmetric rolling process. Two-scale constitutive law was used by implementing an elasto-plastic self-consistent scheme into the Finite Element code (ABAQUS/Explicit). The model was applied to study the asymmetric rolling. Such a deformation process induces heterogeneous mechanical fields that were reproduced by the model thanks to the crystallographic nature of constitutive law used. The studied material was processed, at room temperature, in one rolling pass to 36% reduction. The resulting material modifications were compared with predictions of the two-scale model. Namely, the calculated textures were compared with experimental ones determined by X-ray diffraction. Especially, detailed quantitative analysis of texture variation across the sample thickness was done. The influence of this texture variation on plastic anisotropy was studied. The advantages of asymmetric rolling process over symmetric one were identified. The main benefits are a nearly homogeneous crystallographic texture, reduced rolling normal forces and homogenization of plastic anisotropy through the sample thickness.

Open access

W. Ścięźor, G. Kiesiewicz, R. Kowal, K. Franczak, J. Grzebinoga, A. Mamala and P. Kwaśniewski

Abstract

Modern manufacturing methods of non-ferrous metals, especially aluminum and its alloys, are more and more often based on integrated technologies combining multiple operations in a single process. One of the most popular methods for producing flat components by cold working is twin roll casting technology (TRC). It allows to eliminate from manufacturing the extremely expensive hot rolling operation, as the TRC semi-product (strip) can be directly cold rolled. The results of mechanical and electrical properties and structure examination of strips after casting were presented in the paper. The effect of cold rolling parameters on post-process mechanical properties and structure of sheets was investigated too.

Open access

A. Zieliński, J. Dobrzański, H. Purzyńska, R. Sikora, M. Dziuba-Kałuża and Z. Kania

Abstract

This article presents the results of investigations on HR6W alloy and Sanicro 25 steel and the dissimilar welded joint made of them. The characteristic images of microstructure of the investigated materials in the as-received condition and following the creep test, observed with a scanning electron microscope (SEM), are shown. The X-ray analysis of phase composition of the existing precipitates was carried out. The method for evaluation of creep strength based on abridged creep tests carried out at a temperature higher than the design one is presented. The obtained results do not deviate from the values of creep strength determined in long-term creep tests. The maximum difference in creep strength of the investigated materials is ±20%, which is in compliance with the acceptable scatter band. The methodology presented can be used for verification of creep strength (life time) of the material of finished components to be operated under creep conditions.