MATERIALS ENGINEERING, Vol. 17, 2010, No. 2
published on September 2010

CONTENTS and ABSTRACTS

Iždinská, Z., Nasher, A., Iždinský, K. (pp. 1-5)
THE STRUCTURE AND PROPERTIES OF COMPOSITE LASER CLAD COATINGS WITH Ni BASED MATRIX WITH WC PARTICLES Full text (PDF 1310 kB)
In this work, the influence of the processing conditions on the microstructure and abrasive wear behavior of composite laser clad coatings with Ni based matrix reinforced with 50% WC particles is analyzed. Composite powder was applied in the form of coatings onto a mild steel substrate (Fe–0.17% C) by different laser powers and cladding speeds. The microstructure of the coatings was analyzed by scanning electron microscopy (SEM). Tribological properties of coatings were evaluated by pin-on-disc wear test. It appeared that the hardness of the matrix of composite coatings decreases with increasing cladding speed. However, wear resistance of composite coatings with decreasing hardness of Ni based matrix increases. Significantly enhanced wear resistance of WC composite coatings in comparison with Ni based coatings is attributed to the hard phase structures in composite coatings.

Cosmi, F., Bernasconi, A. (pp. 6-10)
ELASTICITY of SHORT FIBRE REINFORCED POLYAMIDE: MORPHOLOGICAL AND NUMERICAl ANALYSIS OF FIBRE ORIENTATION EFFECTS Full text (PDF 372 kB)
The fatigue behaviour of injection moulded short fibre reinforced polymers depends upon fibre orientation, as shown in experiments conducted with notched specimens injected through different injection gates. The different fatigue behaviour is mainly related to the different local elastic properties, as determined by the different fibre orientation patterns, resulting into different strain distributions. In order to quantify the relationship between fibre orientation and elastic constants, the Cell Method was applied to volumes extracted from the specimens, reconstructed by micro-tomography.

Rosipal, M., Neslušan, M., Ochodek, V., Šípek, M.(pp. 11-14)
APPLICATION OF BARKHAUSEN NOISE FOR ANALYSIS OF SURFACE QUALITY AFTER MACHINING Full text (PDF 215 kB)
This paper deals with application of Barkhausen noise for analysis of surface integrity in turning and grinding operations. The stress state is analyzed in relation to tool wear. The results of measurements show that the residual stresses are not homogenous on the machined surface. This homogeneity depends on tool wear and stability of cutting process. Application of non-destructive testing through the Barkhausen noise is more suitable for grinding operations. Application of Barkhausen noise testing for turning operation will require the next research.

Zatkalíková, V., Bukovina, M., Škorík, V., Petreková, L.(pp. 15-19)
PITTING CORROSION OF AISI 316Ti STAINLESS STEEL WITH POLISHED SURFACE Full text (PDF 1377 kB)
AISI 316Ti is Cr–Ni–Mo austenitic stainless steel with the high Pitting Resistance Equivalent Number (PREN). The effect of the surface finishing by polishing on the pitting corrosion resistance was tested in aggressive 5% FeCl3 solution. The immersion tests were curried out at the temperature 30, 50, 80 °C. The electrochemical cyclic potentiodynamic tests were carried out in the same solution at temperature 30 and 50 °C. The evaluation of the corrosion resistance arose from the comparison of the results of the immersion and the cyclic potentiodynamic tests.

Gasiak, G. – Baran, S.(pp. 20-23)
INFLUENCE OF NON-PROPORTIONAL BENDING WITH TORSION ON FATIGUE LIFE OF CONSTRUCTIONAL STEELS IN THE RANGE OF CRACK INITIATION AND PROPAGATION Full text (PDF 355 kB)
The fatigue tests of constructional steels 10HNAP and 18G2A under cyclic bending with torsion allowed to determine influence of the phase displacement angle ? on the steel life. It has been shown that increase of the phase displacement angle from ?=00 to ?=600 and the ratio of bending moment amplitude Mag to torsional moment amplitude Mas equal to 1.33; 2 and 4 caused a strong increase of life of the tested specimens. The maximum increase of the fatigue life of specimens made of 10HNAP steel was 73% (Mag/Mas=2, ?=450). In the case of specimens made of 18G2A steel, the maximum increase was 58% (Mag/Mas=2, ?=300)


© University of Žilina, Faculty of Mechanical Engineering, ISSN 1335-0803