Microstructural characterization of sintered pellets of Fe-15Wt.% ZrO₂ and Fe-15Wt.%Y₂O₃-5Wt.%Ti model ODS systems

The objective of the present work is to understand the dispersion, interaction of dispersoid and retention of quantity of dispersoid within the high energy ball milled powder matrix upon vacuum sintering in Fe-15Wt.%ZrO₂ and Fe-15Wt.%Y₂O₃-5Wt.%.Ti model Oxide Dispersion Strengthened (ODS) alloys. Grain boundaries of sintered Fe-15Wt.%ZrO₂ were decorated with coarsened ZrO₂ network, which was attributed to grain boundary dragging and enhanced grain boundary diffusion. ZrO₂ retained in Fe-15Wt.%ZrO₂ matrix refined to fine nanometer size of 10 to 20 nm where as in the grain boundary, the size of ZrO₂ were found to be ∼ 500 nm. Retaining the finer size in the matrix at higher temperatures, typically 110 °C for 10 hr, is considered a promising result. On the other hand, size of Y-Ti-O complex oxide in the Fe-15Wt.%Y₂O₃-5Wt.%. Ti ranged between 10-20 nm, and the same was 100 nm in the grain boundary. (author)