Effect of Production Parameters on the Properties of Composite Wires

Nowadays, metal matrix composites have many new areas of application owing to their excellent properties - for example their great tensile strength and high Young’s modulus with its relatively low weight. The aim of this work is the examination of ceramic fibre-reinforced aluminium matrix composite wires made via continuous process. Furthermore, the research will outline the double composite products that are composite wire-reinforced metal matrix composites. Double composites are examined by tensile tests and bending tests. A lot of experiments have been done on the thermal aging of composite wires and on measuring the impact energy of thermal-aged specimens. The mechanical test shows us that structures reinforced with the composite wires have a notably higher load-carrying capacity than a structure reinforced directly with fibres or a structure without any reinforcement

Fabrication Methods of Double Composites

This study shows an example for the application of the medium pressure infiltration technique for production of double composite. Prefabricated composite wires were applied as reinforcement in AlSi12 matrix. The reinforcing composite wires contain Nextel 440 ceramic fibres in pure (99,5%) aluminium matrix. These composite wires were produced by continuous infiltration process. I-profiles were fabricated using the composite wires for bending tests. These tests were done on composite wire reinforced and unreinforced pure AlSi12 samples and the results were compared. The interaction between the composite wire and AlSi12 matrix was examined by optical microscopy. The results of the examinations show strong contact between the reinforcement and secondary matrix and all of the reinforced specimens have higher bending strength than the unreinforced ones

Trackability Measurement of Coronary Stent in a Coronary Vessel Modell

The EN 14299 standard describes in vitro tests of stent and stent system which are specified more precisely and cover a number of additional parameters. In this paper examination of bare metal coronary stents are shown, such as the trackability force measurement. The measurement of the system’s trackability was performed using an in vitro coronary vessel model with the method worked out by us. The trackability is a very important property of the stent system

Analysis of deformations during the chip removal

During the cutting, because of coactions of the workpiece and the tool, an important, plastic shape transformation happens in a slim layer of the workpiece. This strain depends not only on the machining parameters, but on the material-quality too. Locally differing shape transformation can be detected especially in case of materials that own a big extent of anisotropy of mechanical parameters (e.g.: elastic modulus). In such materials the differences of the orientations of crystallites influence the surface roughness, too. In my study the results of examinations were made on OF-Cu and Al samples by an „in situ” (with videocamera) observation of the chip removal, and by the measuring of 1., the shape transformation of the chipped surface and the removed chips, and 2., change of micro hardness. We wanted to know, what effects each parameters of the anisotropy and cutting have on the workpiece’s plastically deformed layers- size and features

Examination of the coatings of coronary stents

In our study the main properties of coated coronary stents are shown, such as foreshortening, recoil, surface features and failures and the expansion properties. The types and the effects of active and passive coatings are introduced. The results of our examinations with different coated coronary stents are shown as well

Titán: a fém, amelyet a repülés tett naggyá

A cikkben a szerzô bemutatja a titánötvözetek legfontosabb tulajdonságait, ismerteti a fémtitán gyártására W. Kroll által kidolgozott módszert, és szemléletes illusztrációkon keresztül betekintést nyújt a titánötvözetek alkalmazásába. Számos adatsor ismertetésével tekinti át a titán világpiacának forgalmi adatait, valamint a közelmúlt hazai titánimportjának szerkezetét

Mechanical Properties Improvement of Low Carbon Steel by Combined Heat Treatments

The improvement of the Mechanical properties of the low Carbon steel and increasing its strength, was the goal of some heat treatment technologies developed in the last twenty years. One of these technologies is the Rapid Heat Treatment (RHT), by which the strength of steel increases with the crystalline grain size decrease obtained from the rapidity of austenitizing, and more strength increase may be obtained, if the action of austenitizing is followed by rapid cooling or quenching, but in this case, ductility will decrease simultaneously by increasing the cooling rate. Another mechanical properties improving heat treatment, is the Intercritical Heat Treatment (IHT), by which the ferrite-pearlite structure of low Carbon steel transforms to Dual-Phase structure of ferrite and martensite resulting increase in strength, while a great deal of its ductility is restored. Authors in this paper report about their experiments carried out on a low Carbon-steel, trying to get the advantages of the two above mentioned technologies, by subjecting the formerly rapid heat treated steel, to intercritical heat treatment,. Applying this treatment on the steel in different temperatures inside the intercritical zone, remarkable results were obtained and reported