Development of nano-oxide dispersed 304L steels by mechanical milling and conventional sintering

In the present work an attempt has been made to synthesize 304L stainless steels alloy powders with nominal compositions 70.00Fe-19.00Cr-11.00Ni (alloy A), 69.00Fe-19.00Cr-11.00Ni- 1.0 Y₂O₃(alloy B), and 69.00Fe-19.00Cr-11.00Ni- 1.0 TiO₂(alloy C), (all in wt.%) by mechanical milling and conventional sintering at 1150°C for 1.0 hour in argon atmosphere. Extensive characterization has been done by SEM, TEM, X-ray diffraction analysis, EDS and particle size analysis at different stages of milling. The minimum crystallite size of powder at final stage of milling was found in the range of 20-25 nm. The bulk hardness values of base and Oxide dispersion strengthened alloys are 2.628 GPa, 4.125 GPa (average) respectively. Wear resistance of TiO₂ dispersed alloy C is found to be superior to that of yttria dispersed alloy B and base alloy A. The nanometric oxide (20-25 nm) particles uniformly dispersed in the alloy matrix contribute to superior mechanical properties.

Keywords:
Oxide dispersion strengthened stainless steels; Mechanical milling; conventional sintering; Scanning electron microscopy; X-ray diffraction analysis; mechanical properties