CORRELATIONS BETWEEN THERMAL PARAMETERS, GRAIN SIZE, DENDRITIC ARM SPACING AND MICROHARDNESS IN DIRECTIONAL SOLIDIFIED AL-ZN AND ZN-AL ALLOYS

ALICIA ESTHER ARES; CARLOS ENRIQUE SCHVEZOV

Orlando, Florida, USA

Congreso; 136th Annual Meeting and Exhibition; 2007

The Minerals, Metals & Materials Society.

Components manufactured from cast aluminum alloys offer theadvantages of lower cost and higher strength-to-weight ratioscompared to ferrous alloys and Zn-Al (ZA) alloys combine highstrength and hardness, good machinability with good bearingproperties. The most common structure in solidification ofmetallic alloys is the dendrite, which can be either columnar orequiaxed and also it is possible to occur the transition from acolumnar to equiaxed (CET) microstructure. In the presentresearch we investigate correlations between thermal parameters,grain size, dendritic spacing and microhardness in directionalsolidified samples of Al-Zn and Zn-Al alloys which presentdifferent types of structures: columnar, equiaxed and the CET. Weanalyze the correlation between cooling rate and dendritic spacingin columnar and equiaxed grains. Also, correlations between grainsize and dendritic arm spacing and the variations in microhardnesswere investigated as a function of both microstructure and loadapplied in the alloys directionally solidified.