Microstructure development of Y–Ti–O dispersion strengthened Cu alloys fabricated by mechanical alloying

A Y–Ti–O oxide-dispersion-strengthened (ODS) Cu alloy has been successfully fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). Excessive cold-welding during high energy ball-milling was effectively suppressed by mixing TiO 2 and pre-alloyed Cu(Y) powders as the raw powders. Microstructural evolutions during the MA and SPS processes and the subsequent annealing were investigated with a focus on the Y–Ti–O nano-oxides. The 12 h ball-milling failed to achieve super-saturations of Y, Ti, and O in Cu, which led to the in-situ formation of various types of oversized Y/Ti-rich oxides with very irregular morphologies during the SPS. With a prolonged ball-milling of 48 h, the subsequent SPS + annealing processes can promote a high density precipitation of ultra-fine Y–Ti–O nano-oxides. These nano-oxides were further identified as Y 2 Ti 2 O 7 mostly, with a high degree of coherency in Cu. Fabricating Y–Ti–O ODS-Cu alloys via MA was thus confirmed to be technically feasible, although the dispersion of nano-oxides desires further improvement. • A Y–Ti–O ODS-Cu alloy was fabricated via mechanical alloying. • Using pre-alloyed Cu(Y) powders reduced cold-welding risks during ball-milling. • A high number of Y–Ti–O nano-oxides (mostly Y 2 Ti 2 O 7 ) were produced in Cu matrix.