Solid State Phenomena Vol. 326

Abstract: In this study, commercial Al-3%Mg aluminium alloy was subjected to ECAP processing using two different ECAP die configurations. The first one – conventional and the second one modified in which a part of the exit channel in the ECAP die, causes twist deformation, to impose extra shear strains to the sample. The local changes in microstructure were characterized by Light Microscopy, SEM equipped with an EBSD facility and TEM. Mechanical properties of the ECAP processed samples were compared based on hardness measurement. The results showed that when ECAP with modified die, the greater grain and crystalline refinement is possible. The microstructures exhibit high dislocation density within subgrains with non-equilibrium and Moiré boundaries. Moreover, the mechanical examinations display a significant improvement in hardness and calculated yield strength when the ECAP process is conducted using a modified die.

Abstract: This study was conducted to study the effect ultrasonic vibrations on the evolution of the microstructure and hardness of the AlMg3 aluminum alloy in a solution treated condition. To understand the process physics in this article, after the deformation the microstructures of the samples before and after deformation were analyzed by the light and electron microscopy, including the electron backscatter diffraction (EBSD) analysis. The result evidently shows that the ultrasonic-assisted deformation has a meaningful influence on the grain refinement – the application of the USV enhances the formation of deformation bands and new sub-grains. This resulted in a certain hardness enhancement.

Abstract: The scope of the work covers the development of the relationship between the chemical composition of surface-modified aluminium and its mechanical properties. This article presents the impact of laser alloying with ZrO powder on the microstructure and mechanical properties of pure aluminium. In order to study the phenomena occurring during the laser alloying process, microstructural studies were carried out using optical microscopy. Additionally, the properties of the obtained alloy were tested - abrasion resistance and hardness measured at low load force. As a result of the alloying process, three distinct zones were identified: the remelting zone (RZ), the diffusion zone (DZ) and the heat affected zone (HAZ). The surface modification resulting from laser alloying increases the hardness and abrasion resistance of the material.

Abstract: Pure niobium substrates were coated using laser cladding method. Pure molybdenum, Yttria Stabilized Zirkonia (YSZ) and corundum (Al₂O₃) powders were used as coating materials. Coatings were deposited on specimens as seperate paths with 3÷10mm width and 40mm of length. Two different laser power 3kW and 4kW were tested during deposition. In order to assess the quality of the Mo-YSZ and Mo-Al₂O₃ coatings, the light microscopy, Scanning Electron Microscopy (SEM), chemical analysis (EDS) and Vickers hardness test investigation were performed. The surface roughness and wear volume were also measured. As a result of YSZ-Mo powder cladding on the Nb substrate the composite layers were obtained without cracks and porosity not exceeding 1 μm. In addition, an increase in hardness of about 450 HV0.5 was revealed. As a result of Al₂O₃-Mo powder cladding on the Nb substrate the composite layers with many voids and cracks were obtained for each of the cladding variants.

Abstract: The properties of the material affect the quality of the manufactured product. Before transferring the finished product to the production phase and sending it to the customer, material tests should be carried out. Examined material properties such as chemical composition, phase composition, grain boundaries influence results obtained after measurements of the chemical composition. The spectrometers used in SEM or as separate XRFs can be compared due to the principle of operation. The main difference in EDS/WDX or XRF is the types of a beam that excite the characteristic X-rays radiation peaks. Unfortunately, both types of spectroscopy have limitations due to materials properties such as the application light chemical elements in alloys an example of B. As well as small quantities of chemical elements in used alloys that affect the obtained results.