Structurally modulated precipitates in a refractory Cr–V alloy

Chromium alloys are considered as high temperature structural materials. Vanadium was substitutionally alloyed into chromium to improve its room temperature ductility. Precipitates, which were indexed as C20Cr25V55 with an orthorombic structure, form in these chromium–vanadium alloys due to the presence of carbon impurities. The distribution, morphology, and crystal defects of the precipitates were studied using electron diffraction, diffraction contrast imaging, and high resolution transmission electron microscopy. One-dimensional structural modulations were determined in these precipitates.

► C20Cr25V55 precipitates with an orthorhombic crystal structure were identified in the Cr–V solid solution with bcc structure.
► One-dimensional structural modulations were determined in the C20Cr25V55 precipitates using HRTEM.
► HRTEM images also reveal the presence of “islands” with the fcc structure included in the orthorhombic phase.