Influence of laser surface hardening on corrosion properties of Al-Zn-Si cast alloy

This work is focused on the effect of the laser surface treatment (laser power 50 and 80 W) on microstructure and corrosion properties of self-hardened AlZn10Si8Mg cast alloy used for engine and vehicle constructions. The electrochemical impedance spectroscopy (EIS) technique and Nyquist plots in a 1M NaCl test solution at 20 °C were carried out. A detailed corrosion study showed that corrosion resistance samples with laser layer were marginally less; probably the presence of chloride ions significantly damaged the Al2O3 film and caused the formation of NaAlO2

Influence of laser surface hardening on corrosion properties of Al-Zn-Si cast alloy

This work is focused on the effect of the laser surface treatment (laser power 50 and 80 W) on microstructure and corrosion properties of self-hardened AlZn10Si8Mg cast alloy used for engine and vehicle constructions. The electrochemical impedance spectroscopy (EIS) technique and Nyquist plots in a 1M NaCl test solution at 20 °C were carried out. A detailed corrosion study showed that corrosion resistance samples with laser layer were marginally less; probably the presence of chloride ions significantly damaged the Al2O3 film and caused the formation of NaAlO2

Possibilities of Fe-RICH phases elimination with using heat treatment in secondary Al-Si-Cu cast alloy

The mechanical properties of Al-Si-Cu cast alloy are strongly dependent upon the morphologies, type and distribution of the second phases. The skeleton like – Al15(FeMn) 3Si2 and needles - Al5FeSi phases were observed in experimental material AlSi9Cu3. The Fe-rich phases morphology was affected with applying two types of heat treatment; T4 and T6, which caused positive changes of mechanical properties especially ultimate tensile strength; gives that for as cast state was Rm = 211 MPa, than at optimum T4 (515 °C/ 4 hours) was Rm = 273 MPa and at optimum T6 (515 °C/ 4 hours with artificial aging 170 °C/ 16 hours) was Rm = 311 MPa

Study of the Properties of the AlSi9Cu3 Alloy Depending on the Ratio of Returnable Material in the Batch

Recycling of aluminium returnable material through its reuse is now an essential component of the production of aluminium alloy castings. The main goal is to find a suitable ratio of the primary alloy and the returnable material in the batch, thus determining the right compromise between the price and the quality of the casting. Experimental alloys were evaluated by thermal analysis, combination of structural analytical techniques and selected mechanical properties. The alloys were also subjected to tearing susceptibility testing. The increase in the returnable material amount resulted in changes in the alloy properties at the first increase in volume to 20%. After exceeding the balanced ratio (50:50), there was considerable degradation of the microstructure, failure to achieve the minimum values of some mechanical properties required by the standard, and the alloy showed increased susceptibility to tearing

Identyfikacja i analiza faz międzymetalicznych w utwardzanych przez starzenie stopach odlewniczych AlSi9Cu3 z recyklingu

Purpose: The influence of age-hardening solution treatment at temperature 515 degrees centigrade with holding time 4 hours, water quenching at 40 degrees centigrade and artificial aging by different temperature 130, 150, 170 and 210 degrees centigrade with different holding time 2, 4, 8, 16 and 32 hours on changes in morphology of Fe-rich Al15(FeMn)3Si2 and Cu-rich (Al2Cu, Al-Al2Cu-Si) intermetallic phases in recycled AlSi9Cu3 cast alloy. Material/Methods: Recycled (secondary) AlSi9Cu3 cast alloy is used especially in automotive industry (dynamic exposed cast, engine parts, cylinder heads, pistons and so on). Microstructure was observed using a combination of different analytical techniques (scanning electron microscopy upon standard and deep etching and energy dispersive X-ray analysis – EDX) which have been used for the identification of the various phases. Quantitative study of changes in morphology of phases was carried out using Image Analyzer software NIS-Elements. The mechanical properties (Brinell hardness and tensile strength) were measured in line with STN EN ISO. Results/Conclusion: Age-hardening led to changes in microstructure include the spheroidization of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases and Al-Al2Cu-Si phases were fragmented, dissolved and redistributed within alpha-matrix. These changes led to increase in the hardness and tensile strength in the alloy.Cel: Badanie wpływu utwardzania przez starzenie przesycanie w temperaturze 515 stopni Celsjusza z czasem przetrzymywania 4 godz., hartowanie wodne w 40 stopniach Celsjusza, starzenie przyspieszone w różnych temperaturach: 130, 150, 170 i 210 stopni Celsjusza, przy czasach przetrzymywania: 2, 4, 8, 16 i 32 godziny na zmiany w morfologii stopów odlewniczych AlSi9Cu3 z recyklingu wzbogaconych żelazem (Al15(FeMn)3Si2) lub miedzią (Al2Cu, Al-Al2Cu-Si). Materiał i metody: Pochodzący z recyklingu (wtórny) stop odlewniczy aluminium AlSi9Cu3 jest powszechnie używany, zwłaszcza w przemyśle motoryzacyjnym (dynamiczne, odkryte odlewy, części silnika, głowice cylindrów, tłoki itp.). Mikrostrukturę odlewów badano stosując kombinację różnych technik analitycznych (elektronowa mikroskopia skaningowa w połączeniu z analizą rentgenowską z dyspersją energii (EDX), standardową i z głebokim wytrawianiem), co pozwoliło identyfikować różne fazy międzymetaliczne. Ocena ilościowa zmian w morfologii tych faz została przeprowadzona przy wykorzystaniu oprogramowania analizatora obrazów (Image Analyzer NIS-Elements). Właściwości mechaniczne (twardość w skali Brinella i wytrzymałość na rozciaganie) były mierzone zgodnie z normą STN EN ISO. Wyniki i wnioski: Utwardzanie przez starzenie prowadzi do zmian w mikrostrukturze, które polegają na sferoidyzacji krzemu eutektycznego, stopniowej dezintegracji, skracaniu i ścienianiu faz międzymetalicznych wzbogaconych żelazem. Fazy Al-Al2Cu-Si podlegały fragmentacji, zostały rozpuszczone i redystrybuowane w osnowie stopu. Zmiany te prowadzą do wzrostu twardości stopu i jego wytrzymałości na rozciąganie

Factors Affecting Food Purchases in Vysočina Region with Focus on Regional Food

The article presents the results of a research study that analyses chosen factors that affect food purchases in Vysočina Region with focus on a regional food. The quantitative research, conducted in 2015 in each district of Vysočina Region (Jihlava, Žďár nad Sázavou, Třebíč, Havlíčkův Brod and Pelhřimov), analysed the opinions of 819 respondents. They were selected by quota sampling methods according to gender. Data have been processed with correspondence analysis; the results show that brand and price are significant factors that influence consumers in Vysočina Region when they buy food, the labels on the food packaging do not seem to be a strong signal of quality. Statistical tests based on contingency tables proved that regional food is strongly preferred by women and consumers over 65 years old

The Influence of the Structure on the Fatigue Properties of Al-Mg Cast Alloy

The article will be focused on monitoring the influence of the structure on the fatigue properties of aluminium alloys for the casting of type Al-Mg. As an experimental material were used aluminium alloys EN AC 51200 and EN AC 51500, supplied in a cast state without a heat treatment. They were produced by the continuous casting method. These alloys were selected on the basis of the chemical composition, where the content of most alloying elements is comparable, only in the case of the concentration of magnesium are these alloys significantly different. Fatigue properties of aluminium alloys were tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where samples were observed on various stages of the fatigue process, their characteristics and differences of fracture surfaces

The Influence of the Structure on the Fatigue Properties of Al-Mg Cast Alloy

The article will be focused on monitoring the influence of the structure on the fatigue properties of aluminium alloys for the casting of type Al-Mg. As an experimental material were used aluminium alloys EN AC 51200 and EN AC 51500, supplied in a cast state without a heat treatment. They were produced by the continuous casting method. These alloys were selected on the basis of the chemical composition, where the content of most alloying elements is comparable, only in the case of the concentration of magnesium are these alloys significantly different. Fatigue properties of aluminium alloys were tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where samples were observed on various stages of the fatigue process, their characteristics and differences of fracture surfaces

Using Deep Etching in the Study of Eutectic Silicon 3D-Morphology in AlSi7MgTi Cast Alloy

The effect of combination grain refinement with AlTi5B1 master (55 ppm) and Sr-modification with AlSr5 master (20, 30, 40, 50 and 60 ppm) on the microstructure, tensile and hardness properties of AlSi7MgTi cast alloy were systematically investigated. Eutectic silicon was studied by optical and scanning electron microscopy after standard (0.5% HF) and deep etching (HCl). Morphology of eutectic Si changes from compact plate-like (as-cast state) to fibbers (after modification). Si-fibbers in samples with 50 and 60 ppm Sr coarsen probably as a result of over-modification. The optimum mechanical properties has the experimental material which was grain refined and modified with 40 ppm of Sr (UTS = 220.6 MPa; ductility = 6.1%, and 82.3 HBW 5/250/15)

Study of the precipitation hardening process in recycled Al-Si-Cu cast alloys

The formation of extremely small uniformly dispersed particles of a second phase within the original phase matrix during heat treatment changed material properties. Therefore the characterization of precipitation had been investigated using high resolution transmission electron microscopy (TEM) and electron diffraction of thin foils for an AlSi9Cu3 cast alloy. For investigation the hardening effect onto mechanical properties of aluminium cast was used heat treatment, which consisted from solution treatment at 515°C / 4 hours (h), followed by quenching into water with temperature 50°C and artificial aging using different temperatures 170°C and 190°C with different holding time 2, 4, 8, 16, and 32 hours. The observations of microstructure and substructure reveals that precipitation hardening has caused great changes in size, morphology and distributions of structural components, the formation of precipitates of Cu phases, and the change of mechanical properties as well