Mechanical Behavior and Fracture Properties of NiAl Intermetallic Alloy with Different Copper Contents

The deformation behavior and fracture characteristics of NiAl intermetallic alloy containing 5~7 at% Cu are investigated at room temperature under strain rates ranging from 1 x 10(-)(3) to 5 x 10(3) s(-)(1). It is shown that the copper contents and strain rate both have a significant effect on the mechanical behavior of the NiAl alloy. Specifically, the flow stress increases with an increasing copper content and strain rate. Moreover, the ductility also improves as the copper content increases. The change in the mechanical response and fracture behavior of the NiAl alloy given a higher copper content is thought to be the result of the precipitation of beta-phase (Ni,Cu)Al and gamma'-phase (Ni,Cu)(3)Al in the NiAl matrix.