鋳造アルミニウム合金の疲労挙動に及ぼす摩擦かく拌プロセスの影響

概要

論文の詳細を見る
Friction stir processing (FSP) was applied to cast aluminium alloy, AC4CH, to modify the microstructure and fully reversed axial fatigue tests have been performed in the as-cast and FSPed conditions in order to study the effect of FSP on the fatigue behaviour. Two different FSPed conditions were evaluated ; as-cast/FSP for which FSP was applied to the as-cast material and FSP/T6 for which as-cast/FSP was post heat treated. In the as-cast/FSP condition, the fatigue strength decreased in the finite life region, but the fatigue limit i.e. the fatigue strength at 10<SUP>7</SUP> cycles significantly increased, compared with the as-cast condition. The fatigue strength in the FSP/T6 condition in the finite life region was higher or slightly lower than in the as-cast/FSP and as-cast conditions, respectively, while the fatigue limit was lower than in the as-cast/FSP condition, but still higher than in the as-cast condition. These complicated fatigue test results obtained were discussed on the basis of microstructural modification resulting from FSP and observations of crack initiation and small crack growth.