S.Y. Zhong

Modeling of structural hardening in oxide dispersion-strengthened (ODS) ferritic alloys

AbstractBased on a rather simple macroscopic and statistical model, experimentally observed variations of yield stress at room temperature in various ODS alloys were theoretically reproduced. For the first time, yield stress values of ODS steels were calculated by taking into account: (1) two interaction mechanisms between dislocations and nanoprecipitates (shearing or bypassing, simultaneously, depending on the particle size); and (2) the whole, possibly multimodal, nanoparticle distributions experimentally determined by SANS. The relative importances of the various strengthening mechanisms can be easily deduced from these calculations.

Simultaneously increasing strength and ductility of nanoparticles reinforced Al composites via accumulative orthogonal extrusion process

ABSTRACT Ceramic particles have been introduced into metal matrices to improve the strength and stiffness of metals, albeit at the cost of the ductility unfortunately. Simultaneously increasing the strength and ductility of metal matrix composites (MMCs) is still a challenge. Accumulative orthogonal extrusion process (AOEP), which disperses nanoparticles and refines grain structures of particles reinforced MMCs via severe plastic deformation, is proposed in this paper. The high strength (687 MPa) and superior ductility (14.8%) are simultaneously achieved in the resultant TiB2 particles reinforced Al–Zn–Mg–Cu matrix composites, and the underlying mechanisms are discussed in terms of particles’ influences. GRAPHICAL ABSTRACT IMPACT STATEMENT An easily realized SPD technology is proposed to effectively optimize the structures of nanoparticles reinforced composites in industrial scale. High strength and good ductility are simultaneously achieved in the resultant composites.