Effect of zirconium and tantalum on the microstructural characteristics of 12YWT ODS steel nanocomposite

In this study Zr and Ta were employed to improve the microstructural characteristics of 12YWT ODS steel. The mechanically alloyed powders containing different contents of Zr (0.5-1.5%) and Ta (0.05-0.15) were extruded at 850 degrees C and microstructural properties of these steel nanocomposites were investigated. Experimental analysis indicated that the addition of zirconium element reduced inter-particle spacing and encouraged Y-Zr-Ti-O complex oxide and ZrO2 phase with average dispersoid size of 10 nm at 1.5% Zr compared to 34 nm for base alloy which can effectively prevent grain growth so that the grain size was obtained about 57 nm rather than 112 nm. The effect of tantalum on reduction of grain size and particle size of dispersoids regardless of zirconium was not noticeable. However, regarding the considerable difference between the total amount of incorporating tantalum and constituent amount in dispersoids, it appeared that this element was mostly in solid solution. (C) 2014 Elsevier B. V. All rights reserved.