ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
Magnesium alloys had gained an increasing interest in recent years due to their promisingproperty profile for light weight constructions. They offer drastic advantages in weight reductions inautomotive industries compared to steel or even aluminium. Therefore they can be used to decreasethe emission of green house gases as requested by the EU directive for the reduction of CO2 emissionsand moreover due to their recyclability they also help to fulfill the requirements from the EU directiveregarding the end of life of vehicles. But still there are some limitations with regard to strength,mostly at elevated temperatures above 130 °C. To overcome these limitations alloy development aswell as process optimization has to be done for further enhancement of the range of magnesiumapplications. This paper will show and discuss the property profiles of the standard magnesium alloyAZ91D compared to the recently developed, heat resistant magnesium alloy MRI153. The alloyshave been processed using normal high pressure die casting (HPDC), New Rheocasting (NRC) andThixomolding® (TM). As methods of investigation tensile and creep tests have been applied. Thecreep properties have been determined in the temperature range of 135-150 °C and loads of50-85 MPa. All these trials have been accompanied by metallographic observations (light opticalmetallography, SEM) and density measurements to investigate the influence of the processing routeson microstructure and the porosity of the materials. It will be shown that the differences in theproperty profile of the chosen alloys are dependent on their different chemical compositions as wellas on different microstructures that are obtained by the different processing routes. While in the caseof AZ91D, TM is showing advantages compared to HPDC for room temperature applications, theNRC in combination with the heat resistant alloy leads to an improvement of creep rates by twoorders of magnitudes
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.43.pdf
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