2012/01/31 by German Samolyuk, G. D. Samolyuk, Y. N. Osetsky +3 · 92 citations
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Advanced Materials Characterization Techniques #Advanced materials and composites #Alloy #Chemistry #Composite material #Condensed matter physics #Creep #Crystallography #Dislocation #Dislocation creep #Ductility (Earth science) #Lattice constant #Materials science #Metallurgical and Alloy Processes #Metallurgy #Peierls stress #Physics #Transition metal #Tungsten #cond-mat.mtrl-sci
paper · pdf · doi:10.1088/0953-8984/25/2/025403
published in Journal of Physics Condensed Matter 25(2), 025403 (IOP Publishing) · 12 pages, 8 figures, 3 tables
arxiv created 2012/08/01 · openalex publication_date 2012/11/29 · arxiv updated 2015/04/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Several transition metals were examined to evaluate their potential for improving the ductility of tungsten. The dislocation core structure and Peierls stress and barrier of 1/2<111> screw dislocations in binary tungsten-transition metal alloys (W(1-x)TM(x)) were investigated using density functional theory calculations. The periodic quadrupole approach was applied to model the structure of the 1/2<111> dislocation. Alloying with transition metals was modeled using the virtual crystal approximation and the applicability of this approach was assessed by calculating the equilibrium lattice parameter and elastic constants of the tungsten alloys. Reasonable agreement was obtained with experimental data and with results obtained from the conventional supercell approach. Increasing the concentration of a transition metal from the VIIIA group, i.e. the elements in columns headed by Fe, Co and Ni, leads to reduction of the C' elastic constant and increase of the elastic anisotropy A = C(44)/C'. Alloying W with a group VIIIA transition metal changes the structure of the dislocation core from symmetric to asymmetric, similarly to results obtained for W(1-x)Re(x) alloys in the earlier work of Romaner et al (2010 Phys. Rev. Lett. 104 195503). In addition to a change in the core symmetry, the values of the Peierls stress and barrier are reduced. The latter effect could lead to increased ductility in a tungsten-based alloy. Our results demonstrate that alloying with any of the transition metals from the VIIIA group should have a similar effect to alloying with Re.