• 作者： 陳文咸; 王東明; 余祥雲
• 作者服務機構： 中正理工學院應用物理系
• 中文摘要： 我們使用超音波雙脈波技術量測純鋁內部經柱形平底壓針壓後所產生之塑性變形區。由於試樣受壓後內部局部性差排密度梯度形成，使第一個入射波由試樣底面反射的回波相位與第二個入射波由試樣前面反射的回波相位不同，該相位差可轉化成輸出之訊號強度差，此強度之變化顯示塑性變形區的形狀分佈。所測得之有效塑性區為一曲面，其平均半徑約為壓針半徑之兩倍，其值和壓針壓入試樣之深度無關。
• 英文摘要： The plastic zone of the commercially pure aluminum under flat end cylindrical indenters was investi-gated by the ultrasonic double-pulse technique. It was observed that the phase change between the rear-faceecho of the first pulse and the front-face echo of the second pulse exhibits a local dislocation densitygradient around the indenter forming a "zone of influence" (or an "effective plastic zone"). This effectiveplastic zone under the punch is curved in its shape. The average distance, R, measured from the center ofthe punch end surface to the plastic zone boundary is found to be approximately twice the magnitude com-pared to the indenter size, for various indenter diameters, d, up to 10 mm with the sample dimensionsabout 13 x 6 x 3 .The normalized plastic zone size, R/d, is found to be independent of the penetrationdepth, δ.
• 中文關鍵字： plastic zone; ultrasonic double-pulse technique; dislocation
• 英文關鍵字： --