Oxide dispersion strengthened ferritic steel fabricated by mechanical alloying and spark plasma sintering

Abstract

The production process of a reduced activation oxide dispersion strengthened ferritic steel with nominal composition of Fe–12Cr–2·5W–0·2Ti–0·25Y₂O₃ (designated 12Cr-ODS) was investigated in this study. Master alloy with designed composition was prepared first, and the powder with two sizes obtained by atomising was prealloyed by mechanical alloying with added Y₂O₃ powder, followed by consolidated spark plasma sintering. Characteristics of the samples were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and relative density, and the mechanical properties such as hardness (HV), bending strength and tensile strength were also tested. Sample with 50% coarse particles and 50% fine particles was found to be of better comprehensive properties. Mechanical properties of the sample changed with the improved microstructure of refining grains and optimised oxide particles that were acquired through annealing. However, further research on the dispersion and properties of oxide particles is needed in the future.

Keywords:

• Master alloy
• Mechanical alloying
• Spark plasma sintering
• Microstructure
• Annealing

Acknowledgement

We thank the National Basic Research Program of China (973 Program) for the financial support through project no. 2007CB209801.