111 超微細粒ZN-Al共析合金の超塑性変形機構および微細組織変化(超塑性と材料および造形法)

概要

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The deformation mechanism in the nanometer grain size range been basically investigated from the results of microstructural observation after superplastic deformation in a Zn-Al eutectoid alloy in which a reverse grain size dependence of superplastisity has been reported. By controlling the aging condition after solution treatment and subsequent quenching two specimens are prepared:the as-quenched specimen with ultrafine-grains of 83nm in diameter and aged specimen with normally fine gains of 2.6μm. As a result of TEM observation on the interior of the grains, dislocations are rare in the as-quenched specimen, while a significant density of dislocations are observed in the aged specimen. This result strongly support the mechanism previously proposed by Mishra et al. that the accommodation process, i.e., the dislocation glide inside the grains becomes more difficult with decreasing grain size in the nanometer grain size range, even though the grain boundary sliding as the major process becomes facilitated.
一般社団法人日本機械学会の論文
2006-09-14