Effect of high-energy ball milling on the microstructure and mechanical properties of Ni-based ODS alloys fabricated using gas-atomized powder

Abstract

In this study, the effects of high-energy ball milling of atomized powder on the microstructure and mechanical properties of a Ni-based oxide dispersion strengthened (ODS) alloy were analyzed. Ni-based ODS alloys were prepared via high-energy ball milling and spark plasma sintering using a gas-atomized powder. The atomized powder with a dendrite structure contains Ni5Y and Al2Ni6Y3 intermetallic compounds, which are not observed in conventional alloys fabricated using elemental powder. These intermetallic phases are refined and decomposed during high-energy ball milling, affecting the formation and dispersion of oxides, which alters the microstructure and mechanical properties of Ni-based ODS alloys. The Ni-based ODS alloys fabricated using ball-milled powders had finer oxide particles and improved oxide dispersion compared to those fabricated using atomized powders. The grain size of the Ni-based ODS alloys fabricated using ball-milled powder was significantly reduced because of the inhibition of grain growth during the sintering process. In addition, Ni-based ODS alloys fabricated using ball-milled powders exhibited improved hardness and high-temperature compressive strength.