CORRELATIONS BETWEEN THERMAL PARAMETERS, GRAIN SIZE, DENDRITIC SPACING AND MICROARDNESS IN DIRECTIONAL SOLIDIFIED Al-Zn AND Zn-Al ALLOYS

ALICIA ESTHER ARES; CARLOS ENRIQUE SCHVEZOV

Orlando, Florida-USA

Simposio; LIGHT METALS 2007; 2007

The Minerals, Metals and Materials Society (TMS)

Components manufactured from cast aluminum alloys offer the advantages of lower cost and higher strength-to-weight ratios compared to ferrous alloys and Zn-Al (ZA) alloys combine high strength and hardness, good machinability with good bearing properties. The most common structure in solidification of metallic alloys is the dendrite, which can be either columnar or equiaxed and also it is possible to occur the transition from a columnar to equiaxed (CET) microstructure. In the present research we investigate correlations between thermal parameters, grain size, dendritic spacing and microhardness in directional solidified samples of Al-Zn and Zn-Al alloys which present different types of structures: columnar, equiaxed and the CET. We analyze the correlation between cooling rate and dendritic spacing in columnar and equiaxed grains. Also, correlations between grain size and dendritic arm spacing and the variations in microhardness were investigated as a function of both microstructure and load applied in the alloys directionally solidified.