Effect of Superplastic Deformation on Cavitation and Mechanical Properties of Supral 100, 150 and 220 Alloy Sheet

摘要

The effect of a commercial superplastic forming process on cavitation induced in Al-Cu-Zr Supral 100, 150 and 220 was studied and post-formed tensile, fatigue, and crack growth rate properties determined. The onset of cavitation occurs at 0.4 to 0.5 true strain, and the amount of cavitation increases linearly with strain. Although the tensile strength of as-formed sheet is only slightly reduced even at high strains and cavitation levels, ductilities are reduced by half. Increased strengths are obtained by post-forming heat treatment, but the strength levels obtained are lower than for rolled, fully heat treated sheet. Fatigue strength and fatigue crack growth rates are adversely affected by high levels of superplastic strain and cavitation.