The effect of solidification rate on microstructure and mechanical properties of an eutectic NiAl–Cr(Mo)–Hf alloy

Abstract

The effect of solidification rate on the solidified structure and mechanical properties of NiAl–28Cr–5Mo–1Hf (at.%) alloy are experimentally investigated in the paper. With the increasing solidification rate, three types of the solidified structure were identified: planar, cellular and dendritic. Microhardness and compressive yield stress of the alloy at the tested temperature range increase with increasing solidification rate varying from 3.33 to 30 μm s −1. The strengthening behavior was attributed to a combined effect of the decrease in average interlamellar spacing and more homogeneous distribution of fine precipitates with the increase in solidification rate.