A Double-Nanophase Intragranular-Oxide-Strengthened Iron Alloy with High Strength and Remarkable Ductility
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INTRODUCTION Most engineering applications call for structural materials that have high strength, fracture toughness, and stiffness.[1,2] Generally speaking, increasing strength compromises toughness and ductility. Oxide dispersion strengthening is a well-known strengthening mechanism to improve the mechanical properties of structural materials. In this regard, oxide dispersion-strengthened (ODS) alloys have been identified as a promising candidate used as the key components in the power and nuclear industries, due to their outstanding strength
MINGLI QIN, DEYIN ZHANG, GANG CHEN, BAORUI JIA, HAOYANG WU, WANGWANG DING, LIN ZHANG, YU YAN, and XUANHUI QU are with the Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, P.R. China. Contact e-mail: [email protected] Manuscript submitted September 21, 2018. Mingli Qin and Deyin Zhang contributed equally to the work.
METALLURGICAL AND MATERIALS TRANSACTIONS A
and creep resistance.[3–6] The ultrafine and uniformly distributed dispersoids in the metal matrix can act as effective obstacles to dislocation motion and grain boundary migration, further improving mechanical properties of the ODS alloys.[3,7–10] ODS alloys are usually produced by powder metallurgy, including mechanical alloying (MA) and subsequent hot consolidation, e.g., hot extrusion or hot isostatic pressing. Although the MA process is well known to facilitate dispersing nanosized oxide particles in the metal matrix, it is not only an energy- and time-consuming process but causes unwanted contaminations arising from mechanical milling. Additionally, oxide particles in ODS alloys prepared by solid–solid or solid–liquid syntheses processes tend to be distributed in grain boundaries, leading to stress concentrations, localize strains, and thus cracking near them at the grain boundaries.[11] The resultant ODS alloys have a high strength but inadequate ductility. Recently, however, Sun et al.[11] reported that a liquid–liquid blends route is effective to prepare nanostructured high-strength Mo alloys with an unprecedented tensile ductility. Compared with the solid–solid or solid–liquid synthesis routes, the liquid–liquid synthesis achieved uniformly dispersed nanosized oxide particles into the grain interior, achieving high strength and ductility of ODS Mo alloys. Consequently, the key to fabricate high-performance ODS alloys is the refinement and homogeneous distribution of dispersoids into the matrix grain interior. In this study, we demonstrated a versatile facile technique (as shown in Figure 1) to produce a nanocrystalline iron alloy with uniformly dispersed nanosized Y2O3 into the grain interior by the solution combustion process followed by spark plasma sintering (SPS). Solution combustion synthesis (SCS) is a promising liquid–liquid mixing process involving rapid combustion reaction of aqueous solution.[12–15] it is also easy to handle, scalable, as well as time- and energy-saving, showing promising perspectives for the large-scale synthesis nanoscal
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