ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The practical phase constituent diagram has been used to determine the composition of alow alloying τ-type Mg-Zn-Al alloy, which has a nominal element content of 7wt%Zn and 3wt%Al(ZA73), as a basis for further improvement of τ-type alloy through appropriate thermal processing andmicro-alloying. The microstructure and solidification characteristics of the alloy have beenexperimentally examined using optical microscopy, scanning electron microscopy, X-ray diffraction,and differential scanning calorimetry analysis. The results confirm that the as-microstructure of ZA73alloy consists of globular equiaxed dendrite with τ phase as the only secondary phase evenlydistributed in interdendritic spacing. Solidification sequence has been proposed with the help of DSCanalysis and Mg-Zn-Al ternary liquidus projection phase diagram. Consistent with previous observedresults for τ-type Mg-Zn-Al alloy, due to the decrease of element contents, ZA73 alloy has higherliquidus temperature (~627°C) and wider solidification range (~283°C), while at the mean time lowerstarting temperature of the second phase transformation (~354°C), compared to higher elementcontaining ZA104 alloy. The phase constituent diagram has been shown to be a practical and effectivetool for predicting the as-cast microstructural constituent of high zinc Mg-Zn-Al alloys under normalpermanent mould solidification condition
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/16/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.546-549.123.pdf
