Solidification crack propagation and morphology dependence on processing parameters in AA6061 from ultra-high-speed x-ray visualization
Nadia Kouraytem, Po‐Ju Chiang, Runbo Jiang, Christopher Kantzos, Joseph Pauza, Ross Cunningham, Ziheng Wu, Guannan Tang, Niranjan D. Parab, Cang Zhao, Kamel Fezzaa, Tao Sun, Anthony D. Rollett
Abstract
Solidification or hot cracks are commonly observed defects in a number of metal alloys and may lead to deterioration of additively manufactured parts quality. In this study, ultra-high-speed x-ray radiography experiments enable the observation and characterization of bundles of hot-cracks that form in monobloc AA6061 substrate. The crack bundles are related to meltpool characteristics and pore formation. Crack propagation rate is also presented for the case of a crack that initiates from a pore. Two types of relevant pore formation are also described, namely keyhole porosity and crack-remelting porosity. The results of this study are expected to facilitate the validation of theoretical and numerical models of solidification cracking.