Rapid solidification of Ti rare earth alloys can produce a fine rare earth oxide dispersion. A stable distribution of rare earth oxides in a hexagonal Ti matrix has been shown to increase the flow stress at both room and elevated temperatures. Previous studies have investigated the precipitation phenomena in Ti-erbium Ti-Ianthanum, and Ti-Al-gadolinium alloys. The present research addresses oxide precipitation in a Ti-cerium alloy as a result of rapid solidification processing.
Samples of Ti-4 wt% Ce were rapidly solidified by splat quenching 300 mg droplets, after free fall in a 100 m drop tube, onto a copper block. Pyrometer measurements and heat flow calculations estimate that the liquid drop was undercooled approximately 200 K below its equilibrium melting temperature (Tm=1920 K) at impact. Thin foils from the splats were prepared by punching 3 mm diameter discs and twin-jet electropolishing in a solution of 3% perchloric acid, 37% n-butylalcohol, and 60% methanol at 240 K and 34 V. The TEM investigations used a Philips CM12, a CM30, and an EM420T.