COLUMNAR-TO-EQUIAXED TRANSITION IN METAL MATRIX COMPOSITES

A.E. ARES; C.E. SCHVEZOV

San Antonio, Texas

Simposio; RECENT DEVELOPMENTS IN THE PROCESSING, CHARACTERIZATION, PROPERTIES, PERFORMANCE AND APPLICATIONS OF METAL MATRIX COMPOSITES; 2013

The Minerals, Metals and Materials Society

The present work is focused on the study of the effect of the directional heat extraction on the SiC distribution in the aluminum matrix composite (MCMM) and on the columnar  to  equiaxed (CET) position in samples directionally solidified. ZA-27 alloy matrix is reinforced/filled with ceramic-particulates of Silicon-carbide (SiC), vertically directionally solidified and the following parameters were measured: cooling rates, temperature gradients, interphase velocities and the influence of them on the solidification microstructure of the MMMs is analyzed. Recalescence was detected and measured during the equiaxed transition being of the order of 3.5°C to 1.1°C. The values of the temperature gradients reached minimum during the CET in most cases even negative (between -3.89 K to 0.06 K). The interphase velocities vary between 0.07 to 0.44 mm/s at the transition.