| The purpose of this study is to investigate the deformation characteristics and microcrack initiation behavior depending on the microstructure of Widmanstatten-α(Wα) and equiaxed-α(Eα) in a Ti-6Al-4V Alloy. In Wα structure, microcracks were observed to form along the α/β interfaces, the colony boundaries and the grain boundary α layers both in tension and fracture tests. In Eα structure, most of microvoids were found to form at the α/β interfaces. The lower tensile strength and ductility of Wα structure was mainly due to the strain localization along the prior β grain boundaries and colony boundaries, which was preceded by the easy slip transfer through α/βinterfaces within the colony. The large increase in fracture toughness of Wα structure was, however, primarily attributed to the crack path deviation depending on the colony orientation. |
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