AE周波数解析による銅ベリリウム・コバルト合金の破壊じん性ならびに微視破壊過程の評価

概要

論文の詳細を見る
Using the Acoustic Emission (AE) technique, the relationship among the AE spectrum, the change of the fracture toughness and micro-fracture mechanism due to the ageing effect have been investigated for commercial Cu-Be-Co alloy. The AE signals could be classified into 6 groups by spectrum analysis through all materials aged at 300℃ and 420℃ for given times. The classified AE signals were plotted along with the load-displacement diagram following the order of emitted time and energy. By AE signal analysis, the fracture toughness and micro-fracture mechanism and its change at the crack tip due to the ageing effect are discussed. At the early stage of deformation, the facet created by the decohesion of the intermetallic inclusion and the precipitations emitted AE, which had a certain frequency component of 200-600 kHz, where the dominent frequency components depend on the ageing process. Increasing the deformation, facet was connected suddenly by the dimple fracture which led to the pop-in crack propagation. In this step, the AE had an audible frequency and the highest energy level was emitted. A model of the micro-fracture process and AE source is proposed, paying particular attention to void nucleation and its coalescence at the crack tip.
社団法人日本機械学会の論文
1986-04-25