Superplastic forming of corrosion resistance CuZnSn alloys

The new commercial Cu-Zn based alloys having excellent hot workability and corrosion resistance were developed. Higher than 200% elongation was observed in the hot tensile test with the alloy sample containing Cu-37.9Zn-1.87Sn-1.91wt%Pb at the temperature range from 500 to 600 degrees C at the initial strain rate of 8.3x10(-4) s(-1). The stress-strain curve showed the typical type of superplastic deformation. The alloy samples were made by the usual method to produce commercial brass. In order to refine the grain size, the temperature of hot extrusion was taken from 530 to 580 degrees C which is lower than the temperature above 700 degrees C generally used. Also the certain ratio of alpha / beta phase was adjusted to increase the sliding between alpha and beta interphase interfaces. The grain size refinement and the ratio of alpha / beta phase adjustment increase the elongation at hot workability range.