Nowadays, a transportation industry creates a lot of metal scrap because production and use of cars are on the increase worldwide. This is based on the fact that increase in the production of cars increases usage of aluminium alloys in transportation applications. Therefore, it is necessary to reduce the production of components from primary aluminium alloy and increase their replacement with secondary-recycledaluminium alloys because the production of recycled aluminium alloys is less expensive and less energy-intensive than the creation of new aluminium alloy through the electrolysis. In addition, the recycled aluminium alloys have comparable microstructural parameters and properties as the same primary aluminium alloys. RECYCLING UND EIGENSCHAFTEN VON SEKUNDÄRALUMINIUM LEGIERUNGEN FÜR VERKEHRSINDUSTRIE Zusammenfassung. Dank weltweiter Produktionserhöhung und Benutzung der Fahrzeuge produziert die Verkehrsindustrie heute viel Metallabfall. Wie steigert die Fahrzeugerzeugung, so steigert auch die Benutzung von Aluminiumlegierungen. Es ist nötig, die Produktion von Aluminiumprodukten aus Primäraluminium zu reduzieren. Die Produkte müssen also durch die Produkte aus Sekundäraluminium eingesetzt werden. Während die Schmelzflusselektrolyse bei der Gewinnung von Aluminium aus Bauxit 100 Prozent Energie verbraucht, sind es beim Recycling etwa vier bis sechs Prozent. Das Aluminium-Recycling leistet deshalb einen beträchtlichen Beitrag zur Einsparung von Energie, und dient damit gleichzeitig auch dem Umweltschutz. Noch dazu, die Legierungen vom Sekundäraluminium haben vergleichbare Eigenschaften wie dieselben Legierungen von Primäraluminium.

R e l a t i o n b e t w e e n M e c h a n i c a l P r o p e r t i e s a n d M i c r o s t r u c t u r e o f C a s t

No abstract

Aluminum alloys are the most important part of all shaped castings manufactured, especially in the aerospace and automotive industries. This work focuses on the corrosion properties of the heat-hardening aluminum alloys commonly used for production of automotive castings AlSi7Mg0.3 and on self-hardening AlZn10Si8Mg. Iron is a common impurity in aluminum cast alloy and its content increases by using secondary aluminum alloys. Therefore, experimental materials were developed, with chemical composition according to standards (primary alloys) and in states with an increasing content of Fe. The experimental aluminum alloys are briefly discussed in terms of their chemical composition, microstructure, mechanical properties and corrosion behavior. Corrosion properties were examined using three types of corrosion tests: exposure test, potentiodynamic tests, and Audi tests. Corrosion characteristics of materials were evaluated using stereo, optical and scanning electron microscopy, energy dispersive X-ray analysis, too. Correlation of pit initiation sites with microstructural features revealed the critical role of iron-rich phases, silicon particles and corresponding alloy matrix.

Al-alloys are preferred in the automotive industry because of theirs lightweight. European Union has on the present big interest of share recycling aluminium, and so increase interest about recycled (secondary) aluminium alloys and castings from them. Recycled aluminium alloys are made out of aluminium scrap and workable aluminium garbage by recycling. Due to the increasing production of recycled aluminium cast alloys is necessary their strict metallurgical control. The mechanical properties and the microstructure are dependent on the composition, melt treatment conditions, solidification rate, casting process and the applied thermal treatment. The mechanical properties depend, besides the morphologies, type and distribution of Si, Cu, Mg and Fe-phases, on the grain size, DAS, porosity distribution or profile. Therefore, study the microstructure of Al alloys is very important. Analysis of microstructure in the AlSi9Cu3 alloy was performed on the SEM. For study and identification of intermetallic phases' was utilized standard (Dix-Keller, 0.5% HF) and deep etching. Deep etching consists of dissolving the alphamatrix in the reagent (30 s in HCl) in order to reveal the three-dimensional morphology of the silicon particles and intermetallic phases. For elemental composition of the specimen were used x-rays analysis (line, point and surface -mapping). Finally the fracture surfaces of Al-Si alloy after impact test in the as-cast state were observed.