Superplasticity and Its Application to Near-Net Shaping of Intermetallic Alloys

摘要

Near-net-shape manufacturing offers the best approach for reducing the cost of a complex-shape component. Among various near-net-shape manufacturing techniques, superplastic forming is best suited for most complex shapes and for hard-to-fabricate materials. This paper describes the newly-developed nickel aluminide intermetallic alloys, use of superplastic forming for near-net-shape processing of these alloys, and mechanical properties and microstructures of the superplastically formed prototype disks out of these alloys. Mechanical properties and microstructures of superplastic disks are also compared with other near-net-shape and conventional processes used for nickel aluminides. Observed mechanical properties of the superplastic disk are explained based on its very fine grain size (10 mu m). Nabarro-Herring creep mechanism was found suitable for explaining the observed creep behavior of nickel aluminide alloys. 10 refs., 15 figs. (ERA citation 14:000875)