Papers by Author: Zdeněk Drozd

Abstract: The dilatation characteristics of the continuosly cast AZ31 alloy and composite with AZ31 matrix reinforced by SiC nanoparticles were investigated in the temperature range of 20-410 °C. The axis of specimens was either parallel or perpendicular to the casting texture. The linear thermal expansion of the alloy as well as the composite was measured in an argon protective atmosphere using a Netzsch 410 dilatometer. The relative elongation and coefficient of thermal expansion are the main experimental results obtained using dilatometry. The temperature dependence of the elastic modulus can be calculated using analysis of the dilatometry results.

Abstract: The Mg micropowder was mixed and ball milled with ceramic nanoparticles. The material was compacted and then hot extruded. Samples have been deformed in tensile as well as compression tests at temperatures between 20 and 300 °C at a constant initial strain rate. The flow stress is significantly influenced by temperature. The yield stress and maximum stress decrease with increasing temperature. Stress strain curves obtained at lower temperatures in tensile tests substantially differ from ones estimated in compression. Stress relaxation tests were conducted in order to find the internal stress as well as to identify possible thermally activated process(-es).