ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
In this paper the microstructure evolution of AZ91HP magnesium alloy casts producedunder different disturbing treatment conditions such as non-disturbing, argon blowing andmechanical stirring in semi-solid state after holding a short time was studied. The results show thatthe grains of AZ91HP alloy casts refined, the secondary dendritic arms grown and the dendrites tendto rosette shape with the decrease of holding temperature. External disturbance can accelerate theevolution process, and the spherical primary α phase formed easily under mechanical stirringtreatment condition. The formation of non-dendritic structure is owing to ripening of the dendriticarms, refinement of the grains and movement of the primary formed solid phases. Disturbingtreatments in semi-solid state induce more equilibrium solidification and decrease the amount ofbrittle β-Mg17Al12 phase. Blowing argon into the refined and modified magnesium alloy in semi-solidstate can obtain homogeneous non-dendritic structure and the net shaped β phase distributed on α-Mgphase boundaries become fine and thin, this may be have a good effect on the mechanical propertiesof the magnesium alloy casts. Due to the low disturbing strength, argon blowing can maintain themetallurgy quality of the semi-solid slurry well, and also have high efficiency to make it. Thistechnology need not new complex equipments and can be practiced in conventional castingconditions, so it may be used in industrialize manufacture
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.116-117.296.pdf
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