Effect of Ti and W on the Mechanical Properties and Microstructure of 12% Cr Base Mechanical-alloyed Nano-sized ODS Ferritic Alloys

Abstract

In recent years, research and development of high-temperature structural materials for ultra-super critical pressure plant with increased energy efficiency have actively been in progress so as to solve global environmental pollution and resource exhaustion issues. Oxide-dispersed-strengthened (ODS) ferritic alloys produced by mechanical alloying (MA) have been developed as alternative materials with very high-temperature strength at the ultra-super critical pressure. In this study, Fe-12%Cr ODS based alloys containing Ti and W have been made and the effects of Ti and W on the high-temperature strength of the alloys were investigated. The results show that high-temperature tensile strength and creep rupture strength of the 12YWT steel containing 0.4% Ti and 3% W were the highest. This is mainly due to the formation of fine complex oxides of Ti-Y-0 by the addition of Ti and their homogeneous distribution. It is also suggested that solid solution hardening by W occurs as a result of uniform distribution of W in solution.