Effect of grain size on the mechanisms of plastic deformation in wrought Mg–Zn–Zr alloy revealed by acoustic emission measurements

2013 ◽  
Vol 61 (6) ◽  
pp. 2044-2056 ◽  
Author(s):  
Alexei Vinogradov ◽  
Dmitry Orlov ◽  
Alexei Danyuk ◽  
Yuri Estrin
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Acoustic Emission ◽  
Mechanisms Of Plastic Deformation ◽  
Zr Alloy

Plastic deformation mechanisms in nanocrystalline metallic materials

2013 ◽  
Vol 22 (3-4) ◽  
pp. 81-88 ◽  
Author(s):  
Ilya A. Ovid’ko
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Grain Boundaries ◽  
Computer Simulations ◽  
Theoretical Models ◽  
Deformation Mechanisms ◽  
Dislocation Slip ◽  
Metallic Materials ◽  
Metallic Structures ◽  
Mechanisms Of Plastic Deformation

AbstractThis article discusses the experiments, computer simulations, and theoretical models addressing the conventional and specific mechanisms of plastic deformation in nanocrystalline metallic materials. Particular attention is devoted to the competition between lattice dislocation slip and specific deformation mechanisms mediated by grain boundaries as well as its sensitivity to grain size and other parameters of nanocrystalline metallic structures.

scholarly journals Influence of grain size on mechanisms of plastic deformation and yield stress

2020 ◽  
Vol 2020 (1) ◽  
pp. 26-32
Author(s):  
K. M. Borysovska ◽  
◽  
Y.M. Podrezov ◽  
S.O. Firstov ◽  
◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Plastic Flow ◽  
Major Influence ◽  
Entire Cross Section ◽  
Physical Yield ◽  
Grain Sizes ◽  
20 Nm ◽  
Mechanisms Of Plastic Deformation

The influence of grain size on the physical yield strength of the polycrystal is considered by the method of cellular automata. The physical yield strength of the polycrystal in this model is defined as the stress at which, the plastic deformation covers the entire cross section of the sample from one edge to another. Three mechanisms of plastic deformation are considered. The first one is an initiation of plastic flow from grain to grain by dislocation pile-ups. The second one is plastic flow in different grains independently of each other under the action of external stress and the third one is intergranular slippage. Computer simulations have shown that at large grain sizes (d > 200 nm) deformation propagates from grain to grain by initiating dislocations pile-ups, since in this case pile-ups are quite powerful and have a large effect on neighboring grains. At average values of grain size (20 nm <d <200 nm) plastic deformation occurs in the grains independently of each other, and the external strain give a major influence on plastic deformation. With further reduction of the grain sizes (d <20 nm) the main mechanism of deformation is intergranular slippage. because in grains of this size are quite large image stresses that do not allow large dislocation clusters. In small grains the image forces are quite large to prevent large dislocation pile-ups formation, but the mass and volume of grain are quite small to turn or slip its under the action of external stresses. In accordance with these mechanisms, on the calculated dependence of the physical yield strength vs grain size, there are three areas with different angles of inclination in logarithmic coordinates. Keywords: yield point, grain size, Hall―Petch low.

Acoustic emission and grain size in plastic deformation of metals

1978 ◽  
Vol 12 (6) ◽  
pp. 531-534 ◽  
Author(s):  
S. Mintzer ◽  
R. Pascual ◽  
R.M. Volpi
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Acoustic Emission

scholarly journals Structural Transformations and Mechanical Properties of Metastable Austenitic Steel under High Temperature Thermomechanical Treatment

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 645
Author(s):  
Igor Litovchenko ◽  
Sergey Akkuzin ◽  
Nadezhda Polekhina ◽  
Kseniya Almaeva ◽  
Evgeny Moskvichev
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Temperature ◽  
Austenitic Steel ◽  
Structural Transformations ◽  
Initial State ◽  
Twin Boundaries ◽  
Metastable Austenitic Steel ◽  
Average Grain Size ◽  
Heating Up

The effect of high-temperature thermomechanical treatment on the structural transformations and mechanical properties of metastable austenitic steel of the AISI 321 type is investigated. The features of the grain and defect microstructure of steel were studied by scanning electron microscopy with electron back-scatter diffraction (SEM EBSD) and transmission electron microscopy (TEM). It is shown that in the initial state after solution treatment the average grain size is 18 μm. A high (≈50%) fraction of twin boundaries (annealing twins) was found. In the course of hot (with heating up to 1100 °C) plastic deformation by rolling to moderate strain (e = 1.6, where e is true strain) the grain structure undergoes fragmentation, which gives rise to grain refining (the average grain size is 8 μm). Partial recovery and recrystallization also occur. The fraction of low-angle misorientation boundaries increases up to ≈46%, and that of twin boundaries decreases to ≈25%, compared to the initial state. The yield strength after this treatment reaches up to 477 MPa with elongation-to-failure of 26%. The combination of plastic deformation with heating up to 1100 °C (e = 0.8) and subsequent deformation with heating up to 600 °C (e = 0.7) reduces the average grain size to 1.4 μm and forms submicrocrystalline fragments. The fraction of low-angle misorientation boundaries is ≈60%, and that of twin boundaries is ≈3%. The structural states formed after this treatment provide an increase in the strength properties of steel (yield strength reaches up to 677 MPa) with ductility values of 12%. The mechanisms of plastic deformation and strengthening of metastable austenitic steel under the above high-temperature thermomechanical treatments are discussed.

Sign in / Sign up

Export Citation Format

Share Document