Alloying effects on high-temperature deformation behavior of nickel aluminide intermetallics.

摘要

The objective of this research is to examine the possibility of using nickel aluminide for high temperature structural applications. NiAl is a desirable candidate based on its low density, high thermal conductivity, high melting temperature, and its proven oxidation resistance. Currently, limited ductility at lower temperatures and low creep resistance at high temperatures limit the capabilities of NiAl.; For this research four different alloys were investigated to determine the effects of alloy strengthening. The three elements are next to one another on the periodic table, which will provide the electron number effect (Mo vs. Nb) and the atomic size effect (Cr vs. MO).; The specimens were tested at constant strain rates ranging from 10 -6 to 10-3 s-1. At high temperatures, the flow stress becomes dependent on strain rate. The materials were evaluated by comparing the flow stress at various applied strain rates. The testing temperatures ranged from 850°C to 1200°C.