Peculiarities of plastic deformation nucleation in nanocrystalline vanadium under shear loading

2018 ◽  
Author(s):  
Dmitrij Kryzhevich ◽  
Konstantin Zolnikov ◽  
Aleksandr Korchuganov
Keyword(s):  
Plastic Deformation ◽  
Shear Loading

scholarly journals Nucleation and development of plasticity in nanocrystalline BCC iron under shear loading

2020 ◽  
pp. 17-22
Author(s):  
K.P. Zolnikov ◽  
◽  
D.S. Kryzhevich ◽  
A.V. Korchuganov ◽  
◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Shear Loading ◽  
Main Role ◽  
Structural Rearrangements ◽  
Second Stage ◽  
Grain Sizes ◽  
Bcc Lattice ◽  
Bcc Iron ◽  
Nanocrystalline Iron ◽  
Mechanisms Of Plastic Deformation

The features of the nucleation and development of plasticity in nanocrystalline iron with BCC lattice under shear were studied. The mechanisms of plastic deformation playing the main role in the development of structural rearrangements during loading were revealed. It was shown that the development of plasticity can be conditionally divided into several stages. The first stage of plasticity development is associated with the formation and propagation of dislocations and twins. At the second stage, intraganular slip and intergranular sliding begin to make the main contribution to plastic deformation. These processes initiate a change in the shape of the grains. At large shear, the deformation behavior of the sample is governed by the migration of the interfaces. Not only grain boundaries migrate but also twin ones do. As a result of migration processes, the grain sizes of the nanocrystalline sample are enlarged.

scholarly journals Effect of T-Shape Shoulder Fillet on the Plastic Deformation Properties of SS400 and LYS160 Steel

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1528
Author(s):  
Chaofeng Zhang ◽  
Chen Shixi ◽  
Xuchuan Lin ◽  
Junhua Zhao ◽  
Quanlong Wang
Keyword(s):  
Plastic Deformation ◽  
Stress Concentration ◽  
Structural Optimization ◽  
Optimization Design ◽  
Shear Loading ◽  
Strengthening Effect ◽  
Ductile Materials ◽  
Deformation Properties ◽  
Degradation Effect ◽  
Ordinary Steel

Shoulder fillets are widely used in the structural optimization design of metal dampers. However, the plastic deformation property of dampers affected by stress concentration, owing to different fillets, has not been explored in-depth. In this study, two typical metal damper materials with different plastic deformation, i.e., ordinary steel SS400 and low-yield-strength steel LYS160, were investigated. The strengthening effect of fillets under different loading is evaluated by comparing the mechanical properties of different fillet heights. Furthermore, the effect of the stress concentration caused by different fillet shapes, based on the failure mode of materials, is discussed. Subsequently, the fatigue degradation effect under the reciprocating shear loading is studied. Based on a series of studies on the deformation properties of fillets in different ductile materials, the basis for the structural optimization design under plastic deformation is provided.

scholarly journals FEATURES OF THE Σ5 AND Σ9 GRAIN BOUNDARIES MIGRATION IN BCC AND FCC METALS UNDER SHEAR LOADING – A MOLECULAR DYNAMICS STUDY

2017 ◽  
Vol 15 (2) ◽  
pp. 285
Author(s):  
Andrey I. Dmitriev ◽  
Anton Yu. Nikonov
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Molecular Dynamics Simulation ◽  
Grain Boundaries ◽  
Shear Loading ◽  
External Stress ◽  
Dynamics Simulation ◽  
Fcc Metals ◽  
Symmetrical Tilt ◽  
Fcc Metal

Molecular dynamics simulation of metallic bicrystals has been carried out to investigate the behavior of the symmetrical tilt grain boundaries under shear loading. Σ5 and Σ9 grain boundaries in Ni and α-Fe were analyzed. It is found that behavior of the defect depends not only on the structure of boundaries but also on the type of crystal lattice. In particular it is shown that under external stress the grain boundary (GB) behaves differently in the BCC and FCC metal. A comparison of the values of displacement of various types of GB due to their migration caused by shear deformation is carried out. The results can help us to understand the features of the plastic deformation development in nanoscale polycrystals under shear loading.

Sem Examinations of Glass Knives

1970 ◽  
Vol 28 ◽  
pp. 282-283
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Tensile Loading ◽  
Resultant Force ◽  
Stress Concentrations ◽  
Edge Chipping ◽  
Surface Flaws ◽  
Edge Defects ◽  
Microscopic Surface

There are two types of edge defects common to glass knives as typically prepared for microtomy purposes: 1) striations and 2) edge chipping. The former is a function of the free breaking process while edge chipping results from usage or bumping of the edge. Because glass has no well defined planes in its structure, it should be highly resistant to plastic deformation of any sort, including tensile loading. In practice, prevention of microscopic surface flaws is impossible. The surface flaws produce stress concentrations so that tensile strengths in glass are typically 10-20 kpsi and vary only slightly with composition. If glass can be kept in compression, wherein failure is literally unknown (1), it will remain intact for long periods of time. Forces acting on the tool in microtomy produce a resultant force that acts to keep the edge in compression.

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