Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Małgorzata Wierzbińska Andrzej Nowotnik"

Procesy wydzielania cząstek faz umacniających z przesyconych stopów AlMgSi DOI:10.15199/28.2015.6.5


  Precipitation processes of strengthening phases' particles from supersaturated AlMgSi alloys The mechanical properties of aluminium alloy AlMgSi - a group 6xxx - allow them to be used in many areas of industries extensively. They are generally used for the production of medium-duty elements of aircraft structures, vehicles and rolling stock. Their highest strength properties are obtained when they were subjected to precipitation strengthening process. Despite of on-going projects carried out by many research's units, there is a strong need to examine the effect of chemical composition, kinetic of precipitation processes from supersaturated solutions and the influence of strengthening phases on aluminium alloys mechanical properties. This is due to both the development of new alloys, as well as the constantly increasing demands on their performance. Therefore, this paper is showing the results of study devoted to determination of the impact of the chemical composition and the precipitation strengthening process parameters on the precipitation sequence of the intermetallic phases (temperature and time) of the supersaturated AlMgSi alloys. The characteristics of the supersatureted solution decomposition sequence was performed based on calorymetry study of alloys group 6xxx. Thus, the temperature of phase precipitation for different heating rate was determined. Based on the calorimetric curves and the ln(Q/T2) of 1000/RT values the values of activation energy for precipitation and dissolution of phase components were established. Key words: stopy AlMgSi, procesy wydzielania, mikrostruktura, fazy umacniające, energia aktywacji. Właściwości mechaniczne stopów aluminium AlMgSi - grupa 6xxx - zapewniają szerokie ich stosowanie w wielu gałęziach przemysłu. Na ogół są używane do wyrobu średnio obciążonych elementów konstrukcji lotniczych, pojazdów samochodowych oraz taboru kolejowego. Swoje największe właściwości wyt[...]

Wpływ długotrwałego wyżarzania ujednorodniającego na mikrostrukturę i właściwości stopu aluminium 6066 DOI:10.15199/28.2015.6.6


  Influence of long-lasting solution annealing on the microstructure and properties of aluminum alloy 6066 The microstructure evolution and changes on the mechanical properties of aluminium alloy 6066 and its homogenization process were investigated. Therefore, the alloy was heat treated at temperature of 565°C for 3, 5, 10, 24, 48 and 72 h and this allowed to determine the influence of holding time on the morphology of microstructure constituents and mechanical properties of the examined 6066 alloy. The microstructure evolution were investigated by light microscope and scanning electron microscope. The results show that the main constituent phase in the alloy - plate-like and needle-like dispersoid of Al5FeSi transformed during homogenization process into spheroidal in shape Al(FeMn)Si phase. Additionally, the following primary phases formed during crystallization: precipitates of silicon and eutectic phases with addition of copper - Q-Al5Cu2Mg8Si6 and θ-Al2Cu were not visible, meaning they completely dissolved in the matrix of α-Al. However, primary precipitates of Mg2Si were being dissolved partially and the remnants of these precipitates with the shape of “chinese script" turn their shape into spheroidal after being heat treated for 48 hours. Key words: 6066 aluminium alloy, homogenizing, microstructure, mechanical properties. W pracy przeprowadzono długotrwałe wyżarzanie ujednorodniające w temperaturze 565°C przez 3, 5, 10, 24, 48 i 72 h i określono wpływ temperatury i czasu wyżarzania na zmiany morfologii mikrostruktury i właściwości mechanicznych stopu aluminium 6066. Ewolucję morfologii składników fazowych mikrostruktury obserwowano za pomocą mikroskopu świetlnego oraz skaningowego mikroskopu elektronowego. Stwierdzono, że podczas wyżarzania ujednorodniającego płytkowe i iglaste cząstki fazy Al5FeSi uległy przemianie w sferoidalne cząstki fazy Al(FeMn)Si. Powstałe podczas procesu krystalizacji stopów pierwotn[...]

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