Effect of the solidifying structures on the wear resistance of Zn-Al alloys

MARIO ROBERTO ROSENBERGER; SCHVEZOV, C. E.; ARES, A.E.

Filadelfia

Conferencia; 18 International conference on wear of materials, WOM 2011; 2011

The effect of the solidifying structures on the wear resistance of Zn-Al alloys is analyzed; for that reason, ingots of diluted Zn-Al alloy (4 %wt and less) were performed in a directional cooling furnace to obtain cylindrical ingots with three regions: one with columnar grains, other with equiaxed grains and in the middle other with a mix of both grains called the Columnar-to-Equiaxed Transition (CET). A representative sample of each region was cut and tested by wear resistance. The dry sliding wear resistance is measured in a pin on ring machine; using a carbon steel disk as counterface, which rotate at 2.7 m/s as tangential velocity while the sample is pressed at 32,4 N of load. The wear resistance were analyzed and compared with the grains size and the secondary spacing of the dendrites. The wear resistance of the equiaxed regions is larger than the resistance for the columnar and transition regions. In all the regions the wear resistance increase when the aluminum concentration increase. At large aluminum composition the wear resistance of equiaxed and columnar regions are the same. A clear relation is observed between the wear resistance and the secondary dendritic spacing, when increase the spacing decrease the wear resistance. The equiaxed region has the larger values of wear resistance and the columnar the less for the same spacing. On the other hand, at lower and larger spacing the wear resistance of the all the structures converge