Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5456713 | Materials Science and Engineering: A | 2017 | 8 Pages |
Abstract
A titanium rod with a novel bimodal microstructure consisting of α-Ti plates of 1-5 µm in width and 10-15 µm in length and ultrafine grained (UFG) α-Ti regions with grain sizes in the range of 100-300 nm was fabricated by in-situ dehydrogenation and thermomechanical consolidation of a nanocrystalline TiH2 powder. The consolidation process combined spark plasma sintering at 800 °C for 5 min and hot extrusion at 1100 °C, and took less than 15 min in total. The titanium rod had a high tensile yield strength of 1052 MPa and a limited elongation to fracture of 2.0%. The high yield strength of the titanium rod can be attributed to the high strength of the UFG regions due to grain boundary strengthening and the increased strength of the α-Ti plates due to O solid solution strengthening associated with the high O content of 0.85 wt% in the titanium rod. A microstructural evolution model involving nucleation and growth of the α-Ti plates, partition of H between α-Ti and β-Ti phases and Ti-H eutectoid reaction has been proposed to elucidate the mechanism for the formation of the bimodal microstructure.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Yifeng Zheng, Xun Yao, Yongjun Su, D.L. Zhang,