TY - JOUR
T1 - Abnormal grain growth in commercially pure titanium during additive manufacturing with electron beam melting
AU - Yamanaka, Kenta
AU - Saito, Wataru
AU - Mori, Manami
AU - Matsumoto, Hiroaki
AU - Sato, Shigeo
AU - Chiba, Akihiko
N1 - Funding Information:
The authors would like to thank Tsuyoshi Saito, Yuichiro Hayasaka, Shun Ito, Yumiko Suzuki, and Yumiko Kodama of the Institute for Materials Research, Tohoku University, for their technical assistance. This research was supported by a Grant-in-Aid for Young Scientists (A) [No. 17H04957 ] from the Japan Society for the Promotion of Science (JSPS); a Grant-in-Aid for Scientific Research in a Priority Area on “Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan; and Research Funding from the Japan Society for Technology of Plasticity .
Publisher Copyright:
© 2019 Acta Materialia Inc.
PY - 2019/6
Y1 - 2019/6
N2 - The microstructural evolution of commercially pure titanium (CP-Ti) was investigated during additive manufacturing (AM) with electron beam melting (EBM). Abnormal grain growth (AGG) was observed throughout all but the top of the specimen, with a mixture of fine and very coarse α (hexagonal close-packed) grains, resulting in relatively large scattering in the Vickers hardness at a given build height. AGG proceeded by the growth of some α grains to a few hundred micrometers in size at the expense of the surrounding substructured fine grains, which were created during EBM but prior to the occurrence of AGG. A small amount of β-phase particles were also produced during rapid cooling after solidification, probably contributing the occurrence of AGG by pinning the grain boundaries. The observations highlight the evolution of a unique, process-specific microstructure during EBM fabrication. Improvement of the scan strategy as well as modification of the chemical composition are needed to obtain a homogeneous microstructure.
AB - The microstructural evolution of commercially pure titanium (CP-Ti) was investigated during additive manufacturing (AM) with electron beam melting (EBM). Abnormal grain growth (AGG) was observed throughout all but the top of the specimen, with a mixture of fine and very coarse α (hexagonal close-packed) grains, resulting in relatively large scattering in the Vickers hardness at a given build height. AGG proceeded by the growth of some α grains to a few hundred micrometers in size at the expense of the surrounding substructured fine grains, which were created during EBM but prior to the occurrence of AGG. A small amount of β-phase particles were also produced during rapid cooling after solidification, probably contributing the occurrence of AGG by pinning the grain boundaries. The observations highlight the evolution of a unique, process-specific microstructure during EBM fabrication. Improvement of the scan strategy as well as modification of the chemical composition are needed to obtain a homogeneous microstructure.
KW - Abnormal grain growth
KW - Additive manufacturing
KW - Commercially pure titanium
KW - Electron beam melting
KW - Substructure
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U2 - 10.1016/j.mtla.2019.100281
DO - 10.1016/j.mtla.2019.100281
M3 - Article
AN - SCOPUS:85063042988
VL - 6
JO - Materialia
JF - Materialia
SN - 2589-1529
M1 - 100281
ER -