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Strain direction dependency of deformation mechanisms in an HCP-Ti crystalline by molecular dynamics simulations.
- Source :
-
Computational Materials Science . Feb2020, Vol. 172, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
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Abstract
- • The deformation path depends strongly on the uniaxial tensile directions. • An intermediated phase (BCC) was firstly found during the HCP → FCC transformation in titanium. • A new formation path of { 10 1 - 1 } twinning relation through BCC stage was observed in titanium. • The pure-shuffle nucleation mechanism of { 10 1 - 2 } twin was found in titanium. In this work, effects of uniaxial tensile directions on the deformation mechanisms of a hexagonal close-packed (HCP) titanium crystalline were investigated by molecular dynamics simulations. Three uniaxial tensile directions, namely the [ 2 1 - 1 - 0 ], [ 01 1 - 0 ] and [ 0001 ] directions, were studied. When the tensile loading was along the [ 2 1 - 1 - 0 ] direction, the parent HCP phase transformed firstly into the body-centered cubic (BCC) phase following the Pitsch-Schrader orientation relationship (OR), and then transformed either into the face-centered cubic (FCC) phase following the Bain path or back to the HCP phase following different variants of the Pitsch-Schrader OR. The new-forming and matrix HCP structures were in a { 10 1 - 1 } twinning relationship with each other. The newly formed FCC phase was in a prismatic-type (P-type) OR with the HCP matrix and in a basal-type (B-type) relationship with the new-forming HCP structure at individual contacting interface. The FCC/HCP interfaces in the P-type OR was immobile while that in the B-type OR propagated by the slip of Shockley partial dislocations. Both FCC/HCP interfaces in the P-type and B-type ORs were observed under high-resolution transmission electron microscope. With the tensile loading along the [ 01 1 - 0 ] direction, deformation mechanism of the system was dominated by the slip and dissociation of prismatic <a> dislocations. The system stretched along the [ 0001 ] direction deformed mainly through the slip and dissociation of pyramidal <c + a> dislocations, as well as through the activation of { 10 1 - 2 } twinning by a pure shuffle mechanism. The present investigation can provide clues in designing titanium alloys with both high strength and good plasticity. [ABSTRACT FROM AUTHOR]
- Subjects :
- *TITANIUM alloys
*MOLECULAR dynamics
*TRANSMISSION electron microscopes
Subjects
Details
- Language :
- English
- ISSN :
- 09270256
- Volume :
- 172
- Database :
- Academic Search Index
- Journal :
- Computational Materials Science
- Publication Type :
- Academic Journal
- Accession number :
- 140096578
- Full Text :
- https://doi.org/10.1016/j.commatsci.2019.109328