ニダン ヤキイレ ショリシタ AL ZN ゴウキン ノ ヒロウ キョウド

P(論文)In this paper, the fatigue strength to repetitive tensile loading in an Al-11 mass%Zn alloy aged at 273K after ordinary guenching or two-step quenching, was studied. The results obtained are summarized as follows. 1) The fatigue strength is much larger in two-step quenching than that in ordinary quenching. 2) The fatigue strength in two-step quenching is almost independent of the holding time between 30 and 600 s at intermediate quenching temperature. But in the case of long holding time, 3.6ks, the fatigue strength is lowered. 3) It is considered that the increase of fatigue strength in two-step quenching is mainly due to the increase of thickness of the soft surface layer.departmental bulletin pape