Solid State Phenomena Vol. 229

Abstract: The complex microstructure of as-cast AlSi7Mg alloy has been investigated. Microstructure observations were done using light microscopy, scanning electron microscopy and transmission electron microscopy. Chemical composition of the microstructure constituents was investigated by means of energy dispersive spectrometry, conducted both during SEM and STEM investigations. Selected area diffraction was used to identify the phases in the alloy. Microstructure of the alloy in the as-cast condition consists of Al-Si eutectic and intermetallic phases in the interdendritic regions. These are: Mg₂Si, α-AlFeMnS, β-AlFeSi and π-AlFeSiMg phases. What is more, number of fine precipitates were found within the α-Al dendrites. Only the occurrence of U1 (MgAl₂Si₂) phase has been confirmed.

Abstract: In the dissertation the influence of overheating of around 250°C above T_liq and modification with phosphorus (CuP10 master alloy) on the microstructure of AlSi17Cu5 cast alloy has been shown. Substantial overheating above T_liq temperature of the alloy, causes complete dissolving of the β (Si) phase. In the liquid alloy, multiple areas are being created of different dissolved silicon content, where, as in the result of the overheating, the homogeneous nucleuses are being partially created. After modification with phosphorus, in liquid alloy, additional heterogenic nucleuses (AlP) of primary silicon crystals are being created. In the close neighborhood of these micro-areas, places depleted of silicon appears, where pre-eutectic α (Al, Me) dendrites crystallize.

Abstract: In the dissertation the influence of overheating of around 250^oC above T_liq on the material reliability of AlSi17Cu5 cast alloy has been shown. On the basis of static tensile test, the following had been determined: HB hardness, tensile strength and yield strength for four, chosen technological variants. The results were the base to verify the thesis of compliance between tested feature arrangement and normal arrangement, and on this ground also material reliability determined with Weibull’s statistic arrangement had been defined. This parameter grasp the interdependence between lasting probability and chosen material property of the alloy.

Abstract: The article presents the course and the results of research on welding conditions and tendency of hot cracking occurrence connected with MIG (CMT or Pulse) welding method choice. EN AW 6082 alloy is considered hard-to-weld by using conventional arc welding processes (MIG-Pulse) due to the heat sensitivity and the tendency to hot cracking in the thin walled joints (weld, HAZ). MIG low energy method (CMT) was developed inter alia to solve this problem.

Abstract: The article presents the course and the results of research on comparison of material and technological welding conditions of EN AW 6082 aluminium alloy using low energy (CMT) and pulsed current (MIG-Pulse) welding methods, as well as discusses the properties of welded joints and the application fields of modern low energy welding devices for joining thin aluminium sheets.

Abstract: This article presents the results of the research on tribological composites with AlCu2SiMn matrix that underwent the process of extrusion. The research was conducted on the composites that underwent extrusion, which was carried out with a pneumatic press with a heated matrix of 14mm and 20mm diameter. The research was carried out under technical dry friction conditions in reciprocating motion. The results allowed to describe the influence of the plastic work direction on the tribological properties of the composites reinforced with silicone carbide and glassy carbon. The process of wearing was conducted in two directions: the perpendicular and parallel to the axis of the extruded composite rod. In the examined composites the tribological wear in the direction perpendicular to the direction of the extrusion was greater than wear in the parallel direction. The difference between the values for the parallel and perpendicular directions to the rod decreases with the increase of the degree of plastic work.

Abstract: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties, thickness and structure of an anodic layer formed on aluminium casting alloys. Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT, abrasive wear test was made with using ABR-8251 equipment delivered by TCD Teknologi ApS and microstructure investigations were made with using a light microscope equipped with an electronic camera configured with a computer on two casting aluminium alloys which both were founding by pressure die casting and gravity casting. The researches included analyse of the influence of chemical composition, geometry, roughness and abrasive wear resistant of anodic layer obtained on aluminium casts.Research limitations/implications Contributes to research on anodic layer for aluminium casting alloys. Practical implications Conducted investigations lay out the areas of later researches, especially in the direction of the possible, next optimization anodisation process of aluminium casting alloys, e.g. in the range of raising resistance on corrosion. Originality of this research was to describe the range of possible applications increases for example as materials on working building constructions, elements in electronics and construction parts in air and motorization industry in the aggressive environment.

Abstract: Investigations of composite materials based on EN AW-AlCu4Mg1 (A) aluminium alloy reinforced with Ti (C,N) particles with weight ratios of 5, 10, and 15% are presented in this paper. The metallographic investigations of composite materials show banding of the reinforcing particles in aluminium matrix after the performed extrusion process. The structure observed in composites materials is oriented parallel to the extrusion direction. The amount of reinforcement particles Ti (C,N) has influence on the mechanical properties of the obtained composite materials. The increase of hardness is observed with the growth of the amount of reinforcement particles. Hardness increased from 89 HV1 for the material without the reinforcing phase to 143 HV1 for 15% of the Ti (C,N) reinforced material.Based on the microstructural investigations of the obtained composite materials, the uniform distribution of the reinforcing particles in the aluminium matrix was also revealed in the obtained structure.

Abstract: In the present study, the microstructure of Mg-5Si alloys with tin, aluminum and manganese was investigated. The microstructure of Mg-5Si alloy consists of the primary coarse Mg₂Si phase, α-Mg solid solution and eutectic α-Mg + Mg₂Si in which the eutectic Mg₂Si phase solidifies in the form of Chinese script particles. The Mg₂Sn phase and α-Mg solid solution with tin appear in the microstructure, when 7 wt.% of Sn was added to the Mg-5Si alloy. Aluminum dissolve in the α-Mg matrix and participates in the formation of Al₂Sn phase. The addition of manganese promotes the formation of Mn₅Si₃ compound.