Elevated temperature tensile properties of powder metallurgy Ni₃Al alloyed with chromium and zirconium

The tensile properties of hot extruded powders of Ni-24.1Al, Ni-19.1Al-8.5Cr, and Ni-17.4Al-7.9Cr-0.5Zr have been evaluated from room temperature to 1000° C. These powder metallurgy materials have a fine grain size that results in relatively little increase in yield stress with increasing temperature compared to coarse-grained or single-crystal materials. The alloy containing chromium and zirconium shows greatly reduced dynamic embrittlement in the temperature range 600 to 800° C where the unalloyed aluminide exhibits brittle behaviour. The Cr- and Cr + Zr-containing alloys deform superplastically above 900° C. The mechanism of superplastic deformation appears to be predominantly grain-boundary sliding.