Superplastic forming of aluminum matrix composite sheets reinforced by sic particles

摘要

Superplastic forming of aluminum alloy matrix composites reinforced by SiC particles was studied from their basic deformation properties in a tensile test to the forming applications of various shape parts by gas pressure. The tensile test was performed at elevated temperatures to characterize the optimum strain rate for superplasticity. It is much higher for the aluminum matrix composite sheets than that of a conventional 7475 alloy sheet. One of the forming tests is an axisymmetric conical part, in wihich the composite sheet is biaxially formed at high strain rate around the suitable rate characterized in the tensile test. It can be successfully formed even in biaxial forming at high strain rate. The others are box shape parts with different geometry, in which the sheet is formed at lower strain rate than that in the conical part forming. The composite sheet can be also successfully formed into box part as well as the conventional 7475 alloy sheet.