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• Main Authors: Yueh-Heng Hsieh, 謝岳衡
• Other Authors: Jiun-Ren Hwang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/zg4333

碩士 === 國立中央大學 === 機械工程學系 === 107 === In this study, we chose Ti-6Al-4V titanium alloy processed by the implemented Electron Beam Welding (EBW) for the experiment. The objectives were as follows. (1) To obtain the materials properties such as fatigue crack growth rate and fracture toughness. (2) To understand the effects of stress ratio on the fatigue crack growth rate. (3) To establish the optimum method for predicting fatigue life of a cracked specimen. The results showed that the anti-crack growth ability of weld bead was better than the base material. The fatigue crack growth rate of welding bead was less affected by the stress ratio. Under the same variable amplitude loading, the fatigue life of weld bead was about four times of base material. Fracture toughness JIC of base material and welding bead was 66 N-mm/mm2 and 30 N-mm/mm2, respectively. With respect to fatigue crack growth life prediction, the static fracture correction model was the most accurate one.