Synthesis and characterization of ODS-304L steels by mechanical alloying

Abstract

Nano-oxide dispersed austenitic stainless steels are extensively used in nuclear industry, high performance pressure vessels, chemical and medical industry due to their superior mechanical properties, good weight to strength ratio, durability and very good corrosion resistance. Strength of the ODS alloys could be appreciably enhanced by uniform dispersion of higher amount of nanometric Y2O3 and TiO2. The present study aims at synthesis of 70.00Fe-19.00Cr-11.00Ni (alloy A), 69.00Fe-19.00Cr-11.00Ni with 1.0 % Y2O3 dispersed (alloy B) and 69.00Fe-19.00Cr- 11.00Ni with 1.0 % TiO2 dispersed (alloy C) all in wt. %, through mechanical alloying followed by conventional sintering. Sintering of the alloy powders (alloy A, alloy B and alloy C) are carried out in argon atmosphere at 1150°C for 1.0 hour. Characterization has been undertaken in different stages of milling like 1h, 5h, 10h, 15h, 20h, 30h and 40h of mechanical alloyed powders and sintered pellets, by X-ray diffraction study (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The XRD peaks of powder gradually get broadened with increase in milling time. Particle size of milled powders have been measured by using particle size analyzer and find the average particle size get reduced from 51.2 ìm to 7.5ìm with increasing milling time. Physical (density and porosity) and mechanical (hardness and wear resistance) properties of the sintered pellets are evaluated. The density of sintered products has been calculated by using Archimedes principle. The sintered density of alloy C (1.0 wt. % TiO2 dispersed) is the best as compared to that of alloy A and alloy B.