OS0111-226 Evaluation of uniaxial deformation behaviour of cast polycrystalline Mg-Zn-Y alloys

2015 ◽  
Vol 2015 (0) ◽  
pp. _OS0111-22-_OS0111-22
Author(s):  
Kentaro KAMURA ◽  
Tsuyoshi MAYAMA ◽  
Kazuma SHIRAISHI ◽  
Michiaki YAMASAKI ◽  
Yoshihito KAWAMURA
2009 ◽  
Vol 623 ◽  
pp. 105-117 ◽  
Author(s):  
Marco Speich ◽  
Wolfgang Rimkus ◽  
Markus Merkel ◽  
Andreas Öchsner

Hollow sphere structures are a new group of advanced lightweight materials for multifunctional applications. Within the scope of this paper, the uniaxial deformation behaviour in the regime of large deformations is investigated. Appropriate computational models are developed to account for the deformation mechanisms occurring under high deformations. Macroscopic stress-strain curves are derived and the influence of different material parameters is investigated.


Author(s):  
D. L. Rohr ◽  
S. S. Hecker

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.


Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 143
Author(s):  
Sergey Nikolaev ◽  
Dmitry Pshenay-Severin ◽  
Yuri Ivanov ◽  
Alexander Burkov

Recently, it was shown that materials with certain crystal structures can exhibit multifold band crossings with large topological charges. CoSi is one such material that belongs to non-centrosymmetric space group P213 (#198) and posseses multifold band crossing points with a topological charge of 4. The change of crystal symmetry, e.g., by means of external stress, can lift the degeneracy and change its topological properties. In the present work, the influence of uniaxial deformation on the band structure and topological properties of CoSi is investigated on the base of ab initio calculations. The k·p Hamiltonian taking into account deformation is constructed on the base of symmetry consideration near the Γ and R points both with and without spin-orbit coupling. The transformation of multifold band crossings into nodes of other types with different topological charges, their shift both in energy and in reciprocal space and the tilt of dispersion around nodes are studied in detail depending on the direction of uniaxial deformation.


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