Effect of Decreasing Temperature Reciprocating Upsetting-Extrusion on Microstructure and Mechanical Properties of Mg-Gd-Y-Zr Alloy

The decreasing temperature reciprocating upsetting-extrusion (RUE) deformation experiment was carried out on Mg-Gd-Y-Zr alloy to study RUE deformation on the influence of microstructure of the alloy. This work showed that with the gradual increase of RUE deformation passes, the continuous dynamic recrystallization (CDRX) process and the discontinuous dynamic recrystallization (DDRX) process occurred at the same time, and the grain refinement effect was obvious. Particulate precipitation induced the generation of DRX through particle-stimulated nucleation (PSN). In addition, after one pass of RUE deformation, the alloy produced a strong basal texture. As the RUE experiment proceeded, the basal texture intensity decreased. The weakening of the texture was due to the combined effect of DRX and alternating loading forces in the axial and radial directions. After four RUE passes, the mechanical properties of the alloy had been significantly improved, which was the result of the combined effect of dislocation strengthening, fine grain strengthening, and second phase strengthening.

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Effect of Cyclic Expansion-Extrusion Process on Microstructure, Deformation and Dynamic Recrystallization Mechanisms, and Texture Evolution of AZ80 Magnesium Alloy

Advances in Materials Science and Engineering ◽

10.1155/2019/3268276 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Yong Xue ◽

Shuaishuai Chen ◽

Haijun Liu ◽

Zhimin Zhang ◽

Luying Ren ◽

...

Keyword(s):

Magnesium Alloy ◽

Dynamic Recrystallization ◽

Grain Refinement ◽

Texture Evolution ◽

Extrusion Process ◽

Basal Texture ◽

Continuous Dynamic Recrystallization ◽

Distributed Structure ◽

Texture Intensity ◽

Az80 Magnesium Alloy

The microstructure, deformation mechanisms, dynamic recrystallization (DRX) behavior, and texture evolution of AZ80 magnesium alloy were investigated by three-pass cyclic expansion-extrusion (CEE) tests. Optical microscopy (OM), electron back-scattered diffraction (EBSD), and X-ray diffraction (XRD) were employed to study microstructure, grain orientation, DRX mechanism, and texture evolution. The results show that the grain sizes decrease continuously with the increase of CEE pass. The grain refinement effect of the first pass is the most remarkable, and there appear a large number of twins. After three-pass CEE, a well-distributed structure with fine equiaxed grains is obtained. With the increase of CEE pass, the deformation mechanism changes from twinning to slipping and the DRX mechanism changes mainly from twinning-induced dynamic recrystallization (TDRX) to rotation dynamic recrystallization (RDRX) and then to continuous dynamic recrystallization (CDRX). The grain misorientation between the new grains and matrix grains deceases gradually, and a relatively small angle misorientation is obtained after three-pass CEE. Grain misorientations of the first two passes are attributed to TDRX and RDRX behaviors, respectively. The grain refinement changes the deformation and DRX mechanisms of CEE process, which leads the (0002) basal texture intensity first decrease and then increase suddenly. Eventually, the extremely strong basal texture is formed after three-pass CEE.

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Geometric Dynamic Recrystallization in an AA2219 Alloy Deformed to Large Strains at an Elevated Temperature

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.1199 ◽

2004 ◽

Vol 467-470 ◽

pp. 1199-1204 ◽

Cited By ~ 9

Author(s):

Rustam Kaibyshev ◽

I. Mazurina ◽

Oleg Sitdikov

Keyword(s):

Dynamic Recrystallization ◽

Equal Channel Angular Extrusion ◽

Large Strains ◽

Specific Process ◽

Continuous Dynamic Recrystallization ◽

Aa2219 Alloy ◽

Continuous Dynamic ◽

The Stability ◽

Average Size ◽

Zr Alloy

The mechanism of new grain evolution during equal channel angular extrusion (ECAE) up to a total strain of ~12 in an Al-Cu-Mn-Zr alloy at a temperature of 475oC (0.75Tm) was examined. It was shown that the new grains with an average size of about 15 µm result from a specific process of geometric dynamic recrystallization (GRX) which can be considered as a type of continuous dynamic recrystallization (CDRX). This process involves three elementary mechanisms. At moderate strains, extensive elongation of initial grains takes place; old grain boundaries become progressively serrated. Upon further ECAE processing, transverse low-angle boundaries (LAB) with misorientation ranging from 5 to 15o are evolved between grain boundary irregularities subdividing the initial elongated grains on crystallites with essentially equiaxed shape. The misorientation of these transverse subboundaries rapidly increases with increasing strain, resulting in the formation of true recrystallized grains outlined by high-angle boundaries from all sides. In the same time, the average misorientation of deformation-induced boundaries remains essentially unchanged during ECAE. It is caused by the fact that the evolution of LABs with misorientation less than 4o occurs continuously during severe plastic deformation. The mechanism maintaining the stability of the transverse subboundaries that is a prerequisite condition for their further transformation into highangle boundaries (HABs) is discussed.

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Regularities of Grain Refinement in an Austenitic Stainless Steel during Multiple Warm Working

Materials Science Forum ◽

10.4028/www.scientific.net/msf.753.411 ◽

2013 ◽

Vol 753 ◽

pp. 411-416 ◽

Cited By ~ 12

Author(s):

Andrey Belyakov ◽

Marina Tikhonova ◽

Zhanna Yanushkevich ◽

Rustam Kaibyshev

Keyword(s):

Stainless Steel ◽

Austenitic Stainless Steel ◽

Dynamic Recrystallization ◽

Strain Rate ◽

Structural Changes ◽

Continuous Dynamic Recrystallization ◽

Warm Working ◽

Fine Grain ◽

Power Law Function ◽

Continuous Dynamic

The structural changes that are related to the new fine grain development in a chromium-nickel austenitic stainless steel subjected to warm working by means of multiple forging and multiple rolling were studied. The multiple warm working to a total strain of 2 at temperatures of 500-900C resulted in the development of submicrocrystalline structures with mean grain sizes of 300-850 nm, depending on processing conditions. The new fine grains resulted mainly from a kind of continuous reactions, which can be referred to as continuous dynamic recrystallization. Namely, the new grains resulted from a progressive evolution of strain-induced grain boundaries, the number and misorientation of which gradually increased during deformation. In contrast to hot working accompanied by discontinuous dynamic recrystallization, when the dynamic grain size can be expressed by a power law function of temperature compensated strain rate as D ~ Z-0.4, much weaker temperature/strain rate dependence of D ~ Z-0.1was obtained for the warm working.

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Effect of ECAP on Microstructure and Mechanical Properties of an Al-Mg-Sc Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.667-669.949 ◽

2010 ◽

Vol 667-669 ◽

pp. 949-954 ◽

Cited By ~ 5

Author(s):

Anna Mogucheva ◽

Rustam Kaibyshev

Keyword(s):

Mechanical Properties ◽

Dynamic Recrystallization ◽

Yield Stress ◽

Three Dimensional ◽

Subgrain Structure ◽

High Angle ◽

Continuous Dynamic Recrystallization ◽

Angular Pressing ◽

Continuous Dynamic ◽

Strain Mechanisms

An Al-4.57%Mg–0.2%Sc was subjected to equal channel angular pressing up to fixed true strains of 1, 2, 4, 8 and 12 at a temperature of 300oC. It was shown that extensive grain refinement occurs in this alloy through continuous dynamic recrystallization. As a result, ECAP can provide the formation of subgrain structure, partially recrystallized structure and fully recrystallized structure. The type of structure evolved is dependent on strain imposed. At ε2, the formation of three-dimensional arrays of low-angle boundaries takes place. Next, in the strain interval from 4 to 8 these low-angle boundaries gradually convert into high-angle boundaries. At ε12, fully recrystallized structure is evolved. Yield stress and ultimate strength gradually increases with increasing strain. Mechanisms of strengthening are discussed.

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Microstructure and Texture Evolution of Mg–Gd–Y–Zn–Zr Alloy by Compression–Torsion Deformation

Materials ◽

10.3390/ma12172773 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2773 ◽

Cited By ~ 1

Author(s):

Ping Xu ◽

Jianmin Yu ◽

Zhimin Zhang

Keyword(s):

Dynamic Recrystallization ◽

Strain Rate ◽

Texture Evolution ◽

Continuous Dynamic Recrystallization ◽

Recrystallization Mechanism ◽

Torsion Unit ◽

Continuous Dynamic ◽

Gleeble 3500 ◽

Torsion Deformation ◽

Zr Alloy

Mg–13Gd–4Y–2Zn–0.5Zr alloy was subjected to compression–torsion deformation at 450 °C with a strain rate of 0.001–0.5 s−1 using a Gleeble 3500 torsion unit. The effects of compression–torsion deformation on the microstructure and texture were studied, and the results showed that with the decrease of strain rate, the texture strength decreased, the number of dynamic precipitated particles increased, the degree of recrystallization increased, and the dynamic recrystallization mechanism changed from a continuous dynamic recrystallization mechanism to a continuous and discontinuous dynamic recrystallization mechanism. Along the direction of increasing radius, the degree of dynamic recrystallized grain (DRX) increased, the number of dynamic precipitated particles increased, and the texture strength slightly increased.

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Effect of Deformation Temperature on Microstructure and Mechanical Properties of Low-Alloyed Copper Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.982 ◽

2018 ◽

Vol 941 ◽

pp. 982-987

Author(s):

Anna Morozova ◽

Yana Olkhovikova ◽

Evgeniy Tkachev ◽

Andrey Belyakov ◽

Rustam Kaibyshev

Keyword(s):

Mechanical Properties ◽

Dynamic Recrystallization ◽

Deformation Temperature ◽

Copper Alloy ◽

Elevated Temperatures ◽

Initial State ◽

Continuous Dynamic Recrystallization ◽

Small Strains ◽

Continuous Dynamic ◽

Kinetics Of

The microstructure evolution and mechanical properties of a copper alloy subjected to deformation at temperatures of 20 °C and 400 °C to total strains from 1 to 4 were examined. The formation of planar low-angle boundaries with moderate misorientations occurs within initial grains at relatively small strains regardless of deformation temperature. Upon further processing the misorientations of these boundaries progressively increase and the new ultrafine grains develop. Continuous dynamic recrystallization takes place during deformation at ambient and elevated temperatures. The kinetics of dynamic recrystallization is discussed in terms of a modified Johnson-Mehl-Avrami-Kolmogorov relationship. The large plastic straining results in significant strengthening, the ultimate tensile strength increases from 190 MPa in the initial state to 440 MPa and to 400 MPa after total strain of 4 at 20 °C and 400 °C, respectively. A modified Hall-Petch relationship is applied to evaluate the contribution of grain refinement and dislocation density to the overall strengthening.

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Microstructure Evolution and Mechanical Properties of Mg-Gd-Y-Zn-Zr Alloy Deformed by Multi-Directional Forging with Decreasing Temperature

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1035.10 ◽

2021 ◽

Vol 1035 ◽

pp. 10-16

Author(s):

Ying Ze Meng ◽

Jian Min Yu ◽

Hui Sheng Yu ◽

Yao Jin Wu ◽

Zhi Min Zhang

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Yield Strength ◽

Dynamic Recrystallization ◽

Room Temperature ◽

Forging Process ◽

Texture Intensity ◽

Coarse Grains ◽

Room Temperature Increase ◽

Zr Alloy

The multi-directional forging process can achieve large plastic deformation, and has great application prospects in industrial production. The Mg-9.55Gd-3.28Y-1.77Zn-0.34Zr (wt%) alloy containing LPSO phase was deformed in different passes and then quenched immediately by the multi-directional forging process with decreasing temperature, and the microstructure and mechanical properties of the alloy were analyzed. It is found that as the number of deformation passes increases, the coarse grains decrease, and the dynamic recrystallization fraction increases. The dynamic recrystallization grains swallow the original grains, promote the continuous refinement of the grains, and greatly improve the uniformity of the microstructure. At the same time, the maximum texture intensity of the (0001) basal plane is significantly reduced, and the pole figure distribution is more dispersed, which is attributed to the random orientation of dynamic recrystallization. Due to the refinement of the microstructure and the weakening of the texture, the tensile strength and yield strength at room temperature increase significantly. After 3 passes of deformation, the alloy has the highest mechanical properties, with tensile strength, yield strength, and elongation reaching 317 MPa, 233 MPa, and 15%, respectively.

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A novel simulation of continuous dynamic recrystallization process for 2219 aluminium alloy using cellular automata technique

Materials Science and Engineering A ◽

10.1016/j.msea.2021.141256 ◽

2021 ◽

Vol 815 ◽

pp. 141256

Author(s):

Lei Liu ◽

Yunxin Wu ◽

Abdulrahaman Shuaibu Ahmad

Keyword(s):

Cellular Automata ◽

Dynamic Recrystallization ◽

Aluminium Alloy ◽

Recrystallization Process ◽

Continuous Dynamic Recrystallization ◽

Continuous Dynamic

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Numerical Modeling of Continuous Dynamic Recrystallization in Sn-Based Solder Connection Under Cyclic Loading

10.1115/ipack2021-73319 ◽

2021 ◽

Author(s):

Marta Kuczynska ◽

Ulrich Becker ◽

Youssef Maniar ◽

Steffen Weihe

Keyword(s):

Grain Size ◽

Dynamic Recrystallization ◽

Cyclic Load ◽

Fe Simulation ◽

Operation Time ◽

Inelastic Strain ◽

Parameter Study ◽

Continuous Dynamic Recrystallization ◽

Gradual Evolution ◽

Continuous Dynamic

Abstract The reoccurring cyclic load imposed onto soldered electronic components during their operation time leads to accumulation of inelastic strains in the structure. On a microscale level, the degree of plastic deformation is determined by the formation and annihilation of dislocations, leading to continuous refinement by creation of new grain boundaries, precipitates relocation and growth. This microstructure rearrangement, triggered by an increasing amount of inelastic deformation, is defined as dynamic recrystallization. This work presents a macroscale modelling approach for the description of continuous dynamic recrystallization observed in Sn-based solder connections. The model used in this work describes kinetics of macroscopic gradual evolution of equivalent grain size, where the initial grain size is continuously refined with increasing accumulated inelastic strain until a saturation grain size is reached. The rate and distribution of dynamic recrystallization is further numerically modelled dependent on the effective accumulated inelastic strain and governing stress multiaxiality. A parameter study of the presented model and its employment in finite element (FE) simulation is further described. Finally, FE simulation of the grain size evolution is demonstrated on an example of a bulky sample under isothermal cyclic mechanical loading, as well as a BGA-like structure under tensile, shear and mixed mode cyclic load.

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