Yttria Dispersion Strengthened Nickel-based Superalloy by Mechanical Alloying

Abstract

Department of Metallurgical Engineering PSG College of Technology Coimbatore – 641 004, Tamil Nadu, IndiaPresent work involves preparation of nano sized yttria dispersed nickel-based superalloy by mechanical alloying (MA) in a planetary ball mill and optimization of process parameters. Nanocrystalline (NC) yttria was synthesized using a simple and economical sol-gel route. Elemental powders of composition Ni-20Cr-3Fe-0.5Ti-0.3Al-0.6Y₂O₃ wt% were mechanically alloyed at various milling times (5–40 h) in dry milling. Purity of the alloy and phase evolution was characterized by XRD. The alloying behaviour, particle size, particle shape and compositional analysis were done by SEM/EDAX. TEM of MA powders showed grain size in the micrometer range. The powders were consolidated by spark plasma sintering at temperatures from 1173–1373 K and microhardness measurements were also done. The sample sintered at 1173 K had the highest hardness; higher than that reported in the literature.

Keywords:

• ODS Ni-based alloy
• Mechanical alloying
• SPS compaction