Metallurgy and Foundry Engineering

INFLUENCE OF DEFORMATION CONDITIONS ON THE RHEOLOGICAL PROPERTIES OF 6xxx SERIES Al ALLOY

Teresa Bajor — 2019-10-14

Knowledge of the characteristics describing the technological properties of the material is the basis for correct numerical simulation and the design of new technological processes or the modernization of existing ones. For each technological process of plastic forming, a set of features should be defined that correctly describe the susceptibility of the material to its shaping in a given process.

The paper presents the results of rheological tests of 6xxx series Al alloy, obtained for deformation parameters corresponding to the process of the extrusion of large-size profiles. The effect of deformation conditions on changes in yield stress was determined. Next, the true values of the mathematical model coefficients describing the rheological properties of the tested material were determined using the inverse method, which is the basis for conducting numerical tests.

MAGNETIC PROPERTIES OF Fe NANOWIRES ELECTRODEPOSITED IN SELF-ORDERED ALUMINA MEMBRANE

Iwona Dobosz — 2019-10-14

The iron nanowire arrays (NWs) were fabricated by DC electrodeposition into hexagonally ordered alumina pores. With the use of X-ray diffraction analysis, the structure of iron wires was determined. The iron wires have the Body Centered Cubic structure. The influence of cathodic deposition potential and parameters of membrane on the magnetic properties of nanowire arrays was investigated. Magnetic properties analyzed by VSM measurements suggest that the easy axis of magnetization follows the nanowire axis, with coercivity increasing with a decrease of nanowire diameter and length. The dependence of the height of Fe wires on the electrodeposition potential was determined. The low cathodic potential and smaller pore diameter are the synthesis parameters most beneficial for large coercivity with easy axis along nanowires.

THE EFFECT OF HEAT TREATMENT ON THE MICROSTRUCTURE AND PROPERTIES OF THE CORROSION RESISTANCE OF THE PROSTHETIC ALLOY WIRONIT EXTRAHART (Co-Cr-Mo)

Joanna Augustyn-Nadzieja — 2019-10-14

The presented study performs an analysis of the effect of thermal treatment on the microstructure and corrosion resistance of the commercial prosthetic alloy Wironit ExtraHart (Co-Cr-Mo). Experiments of thermal treatment, homogenization, oversaturation as well as oversaturation with ageing of the alloys were carried out. Metallographic tests, hardness measurements, EDS analyses and electrochemical investigations were performed. For the examined samples, the corrosion potential (OCP) and polarization curve (LSV) were determined, based on which the corrosion properties in the simulated solution of artificial saliva were established. The results of the obtained tests made it possible to evaluate the effect of the performed thermal treatment on the changes in the properties (hardness) as well as the microstructure and corrosion resistance of the examined alloy Co-Cr-Mo.

CHARACTERISTICS OF Al-Fe SINTERS MADE BY THE POWDER METALLURGY ROUTE

Magdalena Majchrowska — 2019-10-14

The Al/Fe material was prepared by the powder metallurgy route with an additional intermediate stage which was a centrifuge of powder mixture. The application of the centrifuge stage was applied to obtain circular phase distribution of Al-rich phases in a sintered material. Iron powder with a particle size under 100 μm and aluminum powder with a particle size of about 25 μm, were used as starting materials. To determine the effect of centrifuging time on the distribution of Fe-Al particles, scanning electron microscopy (SEM, EDS) and XRD techniques were used. Microstructure observations show the influence of the centrifuging time on the distribution of Fe particles. It was observed that a longer centrifuging time caused changes in the ratio concentration of elements and allowed the growth of the intermetallic phase at the interface between solid Al and Fe particles.