Solid State Phenomena Vol. 308

Abstract: The purpose of this chapter of the book is to present knowledge on the use of laser technology in silicon photovoltaic cell manufacturing processes. Particular consideration was given to the technique of using a disk laser to cut the edges of silicon wafers together with the recognition of the flow of laser micromachining on the quality of cut edges to obtain their minimal deformation. The second topic described is the method of producing point contacts employing laser radiation between a layer of vaporised aluminium and crystalline silicon using the Nd:YAG laser. The results illustrating the impact of the structure and parameters of point contact for a given laser radiation energy on basic electrical parameters for complete, prototype solar cells are included. The chapter in the book provides an overview of the literature on the above topics and presents selected results of experimental works carried out by the authors. The motive for its publication is the need to present selected results of own research carried out in the Welding Department cooperating for many years with the Institute of Engineering and Biomedical Materials (IMIiB) of the Silesian University of Technology and the Institute of Metallurgy and Materials Engineering (IMIM) of the Polish Academy of Sciences in Cracow.

Abstract: Titanium alloys due to their low density and high mechanical properties are a group of materials that are being used willingly nowadays. A promising method of titanium heat treatment is laser surface alloying. Process parameters like laser beam power, its transverse speed, amount of alloying elements and shield gas, have influence on the material. Different chemical composition and morphology can be achieved resulting in a change of properties on the surface of the material. The paper presents the investigation of titanium GRADE 1 processed with iron‐nickel powder using laser alloying. The treatment was performed using a high power diode laser. Different laser beam power values were used.

Abstract: Severe plastic deformation (SPD) processing techniques are applied to polycrystalline metallic materials in order to refine the grain size up to the sub-micrometre or nanometer level. The decrease in grain size to a sub-micrometre level is related to beneficial mechanical properties such as very high strength. The most widely applied SPD method is equal-channel angular pressing (ECAP). In distinction to traditional cold rolling or drawing, SPD techniques frequently employ cyclic strain paths that can lead to an essentially unchanged shape of the material sample after processing. In this paper, multi-axis compression is applied by using the MAXStrain (R) unit to impose cyclic compression in two mutually orthogonal directions. This study is aimed to realize the evolution of microstructure and mechanical properties of AlMg₅Si₂Mn aluminium cast alloy subjected to multi-axis compression. The microstructure of the alloy in the as-cast and as deformed state was characterized by light and scanning electron microscopy. The results reveal that multi-axis compression has a great influence on the evolution of microstructure and final mechanical properties. The enhanced mechanical properties are associated with the progressive formation of refined microstructure which is heterogeneously distributed across the sample.