Papers by Keyword: Al-Mg-Si Alloys

Abstract: The microstructure of Al-Mg-Si aluminium alloys is well characterised when it comes to the initial state of the cast billet or the artificially aged profile. Typically, a gas oven coupled with an induction oven is used to preheat the billets before extrusion. Preheating reduces the flow stress of the aluminium and dissolves the phases that have precipitated during cooling after homogenisation. In this paper, the influence of the gas oven temperature on the partial or complete dissolution of the precipitated phases will be shown. In addition, the negative effect of a wrong choice of parameters on the volume content of the MgSi phases will be shown.

Abstract: The hot tearing susceptibility of Al-6Mg-xSi (x = 0-6.0 wt.%) alloys was studied using constrained rod casting. Addition of Si content resulted in double ternary eutectic reactions and then changed the freezing range and eutectic liquid fraction greatly, which made the hot tearing susceptibility show a И-curve with the increasing of Si content. The И-curve was obviously different from the λ-curve that supported by most researchers.

Abstract: In the first stage of the experiment, the effect of Al10Sr modification and Al5TiB grain refiner and interaction of both additions on the microstructure of AlMg5Si2Mn alloy and Mg₂Si phase morphology was investigated. Then the influence of Al10Sr and Al5TiB addition on nucleation temperatures of various intermetallic phases formed in AlMg5Si2Mn alloy also have been interpreted by the formation of distinct peaks in the first derivative cooling curve and microstructural observations. It was found that modification has a meaningful influence on the microstructure of the investigated alloy as well as the crystallization process

Abstract: In this paper, obtaining by PM of aluminum based materials, characterization of them and Finite Element Analysis (FEA) of compaction were investigated. Sintered aluminum alloys (Al-Cu and Al-Mg-Si) were tested from physical and mechanical point of view and the obtained experimental results were compared with those of sintered bronze powder materials. We studied the compressibility and densification mechanism of Al-Cu mixed powders and for prediction of compaction behavior we used FEA. The data was obtained on the stress distribution in the compacted material and on the deformations occurring throughout the mixed metal powder of the compacted samples. The results of FEA were compared with those obtained experimentally

Abstract: Rolling is a very common technique for shaping sheet metal. It aims to reduce the thickness of a metal sample to adapt it to the usual conditions of use in the industry. Nevertheless, this technique is not without modifying the mechanical and microstructural properties of the materials that can influence the mechanical strength of shaped parts. The purpose of the present investigation is to study the changes in microstructures and micro-hardness of Al-Mg-Si alloy with different rolling reduction in thickness and following artificial aging treatments at 175° C . We notice that the micro-hardness increases with the increasing of the deformation level . Reduction in thickness shows a change in microstructure and texture. Characterization methods used in this work is: Optical Microscopy (OM) and, Vickers microhardness.

Abstract: In this work, the effect of pre-strain cold rolling on thermal stability of friction-stir welded AA6061-T6 alloy was studied. The pre-strain rolling was found to be very effective in suppression of abnormal grain growth during standard post-weld T6 heat treatment. It was also shown that the efficiency of this approach essentially depends on rolling path and the rolling along welding direction was the most effective rolling schedule.

Abstract: The present work deals with the effect of solutionising heat treatment on the features of Al-7Si-0.3Mg (A356) alloy in terms of microstructural modifications and hardness. The microstructure of sand cast and gravity cast alloys are coarse which results in lower strength compared to the alloys cast using modern casting techniques such as squeeze casting which is used for the fabrication of near-net-shaped castings. The influence of enhanced cooling rate on the hardness and microstructure of the squeeze casting technique has been exploited in the present study. In order to optimise the heat treatment process, the microstructure of the gravity and squeeze cast alloys were compared after solution treatment. The quantitative analysis of the microstructure was carried out using an image analyser attached to the optical microscope. The aspect ratio, particle count and circularity of eutectic silicon and SDAS are measured. The squeeze cast alloy is found to have finer microstructure with enhanced properties compared to the gravity cast alloy.