Comparative analysis of microhardness in directionally solidified Zn-27%Al, Zn-27%Al + CSi and Zn-27%Al + Al2O3 alloys and composites

ALICIA E. ARES,; CARLOS E. SCHVEZOV

International Foundry Research

Giesserei-Verlag GmbH

Lugar: Dusseldorf; Año: 2008 vol. 60 p. 6 - 13

0046-5933

ZA castings are competing with cast iron, bronze and aluminum because of various properties and processing advantages. One particular alloy such us the ZA27 has a higher yield stress than other zinc alloys and better friction properties than brass at low velocities and dry contact between the materials. The main objecxtive of this paper is to analize microhardness variations as a function of both sample length and sample width of ZA alloys and composites directionally solidified which present columnar, equiaxed and columnar to equiaxed transitions. Also, to analize microhardness variations as a function of type of composite produced. We noticed that the microhardness value decrease when the load increase and reach almost constant values at higher loads. The results in directionally solidified alloys and composites are compared with those in bulk alloys. We observed that bulk alloys have greater microhardness values than those directionally solidified