Crystallographic features of a variants and ß phase for Ti-6Al-4V alloy fabricated by selective laser melting
Document Type
Journal Article
Publication Title
Materials Science and Engineering: A
Publisher
Elsevier
Place of Publication
Netherlands
School
School of Science
RAS ID
26970
Abstract
The present study investigated the crystallographic features of α variants and β phase for Ti-6Al-4V alloy fabricated by selective laser melting. Theβ fiber texture parallel to the building direction was ascertained on the basis of a reconstruction method realized by the manipulation of stereographic projection. The SLMed alloy has no α/α′ variants selection but contains a special crystallographic area exhibiting random orientation which cannot be reconstructed as a parental columnar β grain with the present introduced method due to its nature as the overlapped area between adjacent melt pools resulting from the heterogeneous nucleation in front of the liquid-solid interface. With increasing the heat treated temperature, α variants selection occurs. Especially at higher temperature of 905 °C, the intergranular β phase following a reversed crystallographic path as “parental β phase”→“α variants”→“intergranular β phase” would be precipitated, therefore the intergranular β phase keeps the same orientation with the parental β phase. Once the alloy was heat treated at 975 °C close to Tβ, the microstructure is characterized by primary α variants selection and a large amount of secondary α widmanstatten structure with a homogeneous orientation which accounts for the lowest tensile strength. The decomposition of twelve α variants proved the BORβ//(0001)α,β//α. The misorientation between two variants sharing a common parentalβ pole with a similar color consisting of all Euler angles was identified to be [0001] α/10.53°.
DOI
10.1016/j.msea.2017.09.068
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Comments
Yang, Y., Chen, J., Wang, H. L., Zhang, Z. Q., Lu, Y. J., Wu, S. Q., & Lin, J. X. (2017). Crystallographic features of α variants and β phase for Ti-6Al-4V alloy fabricated by selective laser melting. Materials Science and Engineering: A, 707, 548-558. https://doi.org/10.1016/j.msea.2017.09.068