Formation of equiaxed grains in selective laser melted pure titanium during annealing
Commercially pure titanium (CP-Ti) has seen major applications in biomedical equipment. The use of selective laser melting (SLM) has become more common concerning the fabrication of CP-Ti components with a complicated shape in biomedical implants, where high strength and ductility are required. Howe...
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Elsevier
2021-03-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785421000089 |
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| author | Cheng-Lin Li Chang-Shun Wang P.L. Narayana Jae-Keun Hong Seong-Woo Choi Jae H. Kim Sang Won Lee Chan Hee Park Jong-Taek Yeom Qingsong Mei |
| author_facet | Cheng-Lin Li Chang-Shun Wang P.L. Narayana Jae-Keun Hong Seong-Woo Choi Jae H. Kim Sang Won Lee Chan Hee Park Jong-Taek Yeom Qingsong Mei |
| author_sort | Cheng-Lin Li |
| collection | DOAJ |
| description | Commercially pure titanium (CP-Ti) has seen major applications in biomedical equipment. The use of selective laser melting (SLM) has become more common concerning the fabrication of CP-Ti components with a complicated shape in biomedical implants, where high strength and ductility are required. However, SLM manufactured CP-Ti often exhibits high strength and low ductility, as well as mechanical anisotropy because SLM process typically results in the formation of long columnar grains comprising of fine acicular α′ martensite. Heat treatment must be preceded to transform the acicular α′ to equiaxed α grain. This study demonstrated that annealing at 650 °C of SLM CP-Ti can create an equiaxed structure, resulting in a weakened texture. The formation of equiaxed grains occurred at two types of microstructural features, acicular α′ and irregular massive (α′m) martensite, which exhibited different sizes, morphologies, and contained different types of substructures under SLM as-fabricated condition. The formation mechanism of equiaxed grains in the α′ region is dominated by the coalescence of acicular α′ of the same variant and the dissolution of α′ into the matrix, whereas the formation mechanism in the α′m region is primarily dominated by the growth of the preexisting subgrains. A small number of equiaxed grains with new orientations were formed in the α′m region. The majority of equiaxed grains were formed in the acicular α′ region and inherited the grain orientations of the preexisting α′ or matrix. Therefore, a similar but weakened texture was inherited from the microstructure of the SLM CP-Ti after annealing. |
| first_indexed | 2024-12-17T20:42:22Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-12-17T20:42:22Z |
| publishDate | 2021-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-9f2b9fd59c564a1d8b1f9ab5c8f409662022-12-21T21:33:15ZengElsevierJournal of Materials Research and Technology2238-78542021-03-0111301311Formation of equiaxed grains in selective laser melted pure titanium during annealingCheng-Lin Li0Chang-Shun Wang1P.L. Narayana2Jae-Keun Hong3Seong-Woo Choi4Jae H. Kim5Sang Won Lee6Chan Hee Park7Jong-Taek Yeom8Qingsong Mei9School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China; Corresponding author.School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, ChinaAdvanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of KoreaAdvanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of Korea; Corresponding author.Advanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of KoreaAdvanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of KoreaAdvanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of KoreaAdvanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of KoreaAdvanced Metals Division, Korea Institute of Materials Science, Changwon, 51508, Republic of KoreaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, ChinaCommercially pure titanium (CP-Ti) has seen major applications in biomedical equipment. The use of selective laser melting (SLM) has become more common concerning the fabrication of CP-Ti components with a complicated shape in biomedical implants, where high strength and ductility are required. However, SLM manufactured CP-Ti often exhibits high strength and low ductility, as well as mechanical anisotropy because SLM process typically results in the formation of long columnar grains comprising of fine acicular α′ martensite. Heat treatment must be preceded to transform the acicular α′ to equiaxed α grain. This study demonstrated that annealing at 650 °C of SLM CP-Ti can create an equiaxed structure, resulting in a weakened texture. The formation of equiaxed grains occurred at two types of microstructural features, acicular α′ and irregular massive (α′m) martensite, which exhibited different sizes, morphologies, and contained different types of substructures under SLM as-fabricated condition. The formation mechanism of equiaxed grains in the α′ region is dominated by the coalescence of acicular α′ of the same variant and the dissolution of α′ into the matrix, whereas the formation mechanism in the α′m region is primarily dominated by the growth of the preexisting subgrains. A small number of equiaxed grains with new orientations were formed in the α′m region. The majority of equiaxed grains were formed in the acicular α′ region and inherited the grain orientations of the preexisting α′ or matrix. Therefore, a similar but weakened texture was inherited from the microstructure of the SLM CP-Ti after annealing.http://www.sciencedirect.com/science/article/pii/S2238785421000089Selective laser meltingPure titaniumPost-heat treatmentEquiaxed grainTexture |
| spellingShingle | Cheng-Lin Li Chang-Shun Wang P.L. Narayana Jae-Keun Hong Seong-Woo Choi Jae H. Kim Sang Won Lee Chan Hee Park Jong-Taek Yeom Qingsong Mei Formation of equiaxed grains in selective laser melted pure titanium during annealing Journal of Materials Research and Technology Selective laser melting Pure titanium Post-heat treatment Equiaxed grain Texture |
| title | Formation of equiaxed grains in selective laser melted pure titanium during annealing |
| title_full | Formation of equiaxed grains in selective laser melted pure titanium during annealing |
| title_fullStr | Formation of equiaxed grains in selective laser melted pure titanium during annealing |
| title_full_unstemmed | Formation of equiaxed grains in selective laser melted pure titanium during annealing |
| title_short | Formation of equiaxed grains in selective laser melted pure titanium during annealing |
| title_sort | formation of equiaxed grains in selective laser melted pure titanium during annealing |
| topic | Selective laser melting Pure titanium Post-heat treatment Equiaxed grain Texture |
| url | http://www.sciencedirect.com/science/article/pii/S2238785421000089 |
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