本文旨在觀察超音波振動對材料行為的影響,為了觀察不同結構之材料且兼顧到拉伸試驗設備之極限抗拉強度,本實驗使用之試片材料為面心立方的鋁合金6061和體心立方的低碳鋼S15C,並以拉伸速率、超音波振幅和超音波加載的應變範圍為因子,實驗結果顯示振幅大小和塑流應力的下降幅度成正比,且拉伸速率越慢,其下降的塑流應力幅度也越大;在同樣的超音波輔助拉伸試驗條件中,面心立方的鋁合金6061會比體心立方的低碳鋼S15C擁有更大幅度的應力下降。;The aim of the study is to observe the impact of ultrasonic vibration on the material behavior. To explore the different types of materials and to balance the ultimate tensile strength, the materials employed in the study are the aluminum alloy 6061 of face-centered cubic and the low-carbon steel SI5C of body-centered cubic. Moreover, tensile speed, ultrasonic vibration, and strain range of ultrasonic loading are considered as the factors. The results of the study demonstrate that the magnitude is positively correlated with the descender of flow stresses. Also, if the tensile speed is slower, the descender of the flow stresses would become larger; likewise, in the same condition of ultrasonic-assisted tensile test, the aluminum alloy 6061 of face-centered cubic has greater stress drop than the low-carbon steel SI5C of the body-centered cubic.