Effects of Artificial Embedded Defect Size and Position on the Fatigue Lives of Additive Manufacturing Ti-6al-4v Alloy

Abstract

Additive manufacturing (AM) components usually contain various defects with different positions and sizes inside, resulting in the great change of fatigue performance with the defect location and sizes. Therefore, in the evaluation of numerous structural factors, the defect size effect is one of the most typical problems in the AM components. This study for the first time investigated the effects of sizes and positions of the artificial embedded defects on the high-cycle fatigue (HCF) lives of the most widely studied AM Ti-6Al-4V alloy. Two sets of samples are selected with artificially embedded defects with different sizes and positions for fatigue tests. Through fractographic observations, fatigue lives analysis, and defects statistics, the influences of defect size and position on the HCF lives were discussed. It is found that the Murakami formula can well describe the HCF lives distribution of the AM Ti-6Al-4V alloy with different artificial embedded defects.

Keywords: additive manufacturing, Ti-6Al-4-V alloy, Artificial embedded defects, High-cycle fatigue, Fatigue crack.