MICROSTRUCTURE AND HIGH-TEMPERATURE DEFORMATION OF THE C15 NBCR2-BASED LAVES INTERMETALLICS IN NB-CR-V ALLOY SYSTEM

The microstructure and the high-temperature deformation behavior of th e C15 NbCr2 intermetallics alloyed with V, which consist of both the C 15 monophase and the duplex structure with the bcc solid solution, are observed by some microscopic techniques and compression tests, The al loys consisting of the C15 monophase microstructure show moderately hi gher 0.2% yield stress than the unalloyed NbCr2, and the same BDTT as that in the unalloyed NbCr2, indicating a moderate improvement of the high temperature deformability, This result is attributed to the large r atomic free volumes between the atomic stacking layers along the {11 1} planes than those of the unalloyed NbCr2. The alloys consisting of the duplex microstructure show lower 0.2% yield stress and considerabl y decreased BDTT than the unalloyed NbCr2. The considerable deformatio n improvement in this group of alloys is attributed to the existence o f the ductile bcc solid solution.