title: Formation of nanostructures in Ni-22Cr-11Fe-1X (X = Y2O3, TiO2) alloys by high-energy ball-milling.
abstract: Powder mixtures of Ni, Cr, Fe and Y2O3 were high-energy ball-milled and subsequently sintered to fabricate Ni-based oxide-dispersion strengthened (ODS) alloys. Nano-sized Y2O3 and/or TiO2 seem to be dissolved in the Ni matrix forming a metastable solid solution during high-energy ball-milling or mechanical alloying (MA) process. The finely grained MA powders with high dislocation density facilitated the decomposition of oxides. The MA powders were consolidated to near-full density by spark plasma sintering at 1100 degrees C for 5 minutes in an Ar atmosphere. The Cr oxides as well as decomposed Y- and Ti-oxides thermally precipitated as oxide particles of several tens nanometers at this temperature, although sintering was carried out during a short time. The SPSed specimen showed a near full densification with almost pore-free microstructures. Examination of fractured surface showed a typical dimple rupture with fine and homogeneous distribution of dispersoids, indicating non-negligible room temperature ductility combined with high mechanical strength.
authors: School of Material Engineering, Andong National University, 388 Songchun-dong, Andong, Gyungbuk 760-010, Korea.
authors: Jiwhan
authors: J
authors: Park
authors: Jinsung
authors: J
authors: Jang
authors: Tae Kyu
authors: TK
authors: Kim
authors: Sung-Jin
authors: SJ
authors: Kim
authors: Jung-Ho
authors: JH
authors: Ahn