scholarly journals Dynamic Recrystallization and Its Effect on Superior Plasticity of Cold-Rolled Bioabsorbable Zinc-Copper Alloys

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3483
Author(s):  
Anna Jarzębska ◽  
Łukasz Maj ◽  
Magdalena Bieda ◽  
Robert Chulist ◽  
Daniel Wojtas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Dynamic Recrystallization ◽  
Copper Alloys ◽  
Reduction Rate ◽  
Mean Free Path ◽  
High Plasticity ◽  
Continuous Dynamic Recrystallization ◽  
Cu Alloys ◽  
Cold Rolled ◽  
Continuous Dynamic

High plasticity of bioabsorbable stents, either cardiac or ureteral, is of great importance in terms of implants’ fabrication and positioning. Zn-Cu constitutes a promising group of materials in terms of feasible deformation since the superplastic effect has been observed in them, yet its origin remains poorly understood. Therefore, it is crucial to inspect the microstructural evolution of processed material to gain an insight into the mechanisms leading to such an extraordinary property. Within the present study, cold-rolled Zn-Cu alloys, i.e., Zn with addition of 1 wt.% and 5 wt.% of Cu, have been extensively investigated using scanning electron microscopy as well as transmission electron microscopy, so as to find out the possible explanation of superior plasticity of the Zn-Cu alloys. It has been stated that the continuous dynamic recrystallization has a tremendous impact on superior plasticity reported for Zn-1Cu alloy processed by rolling to 90% of reduction rate. The effect might be supported by static recrystallization, provoking grain growth and thereby yielding non-homogeneous microstructures. Such heterogeneous microstructure enables better formability since it increases the mean free path for dislocation movement.

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

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.

scholarly journals In-situ characterization of continuous dynamic recrystallization during hot torsion of an Al–Si–Mg alloy

2020 ◽  
Vol 822 ◽  
pp. 153282 ◽  
Author(s):  
David Canelo-Yubero ◽  
Zsolt Kovács ◽  
J.F. Thierry Simonet Fotso ◽  
Domonkos Tolnai ◽  
Norbert Schell ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Mg Alloy ◽  
In Situ Characterization ◽  
Continuous Dynamic Recrystallization ◽  
Hot Torsion ◽  
Continuous Dynamic

scholarly journals Investigation on Sub-Solvus Recrystallization Mechanisms in an Advanced γ-γ’ Nickel-Based Superalloy GH4151

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4553
Author(s):  
Shaomin Lv ◽  
Jinbin Chen ◽  
Xinbo He ◽  
Chonglin Jia ◽  
Kang Wei ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Energy Surface ◽  
Electron Backscatter Diffraction ◽  
True Strain ◽  
Continuous Dynamic Recrystallization ◽  
Nickel Based Superalloy ◽  
Transmission Electron ◽  
Continuous Dynamic ◽  
Backscatter Diffraction

Sub-solvus dynamic recrystallization (DRX) mechanisms in an advanced γ-γ’ nickel-based superalloy GH4151 were investigated by isothermal compression experiments at 1040 °C with a strain rate of 0.1 s−1 and various true strain of 0.1, 0.3, 0.5, and 0.7, respectively. This has not been reported in literature before. The electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) technology were used for the observation of microstructure evolution and the confirmation of DRX mechanisms. The results indicate that a new dynamic recrystallization mechanism occurs during hot deformation of the hot-extruded GH4151 alloy. The nucleation mechanism can be described as such a feature, that is a primary γ’ (Ni3(Al, Ti, Nb)) precipitate embedded in a recrystallized grain existed the same crystallographic orientation, which is defined as heteroepitaxial dynamic recrystallization (HDRX). Meanwhile, the conventional DRX mechanisms, such as the discontinuous dynamic recrystallization (DDRX) characterized by bulging grain boundary and continuous dynamic recrystallization (CDRX) operated through progressive sub-grain merging and rotation, also take place during the hot deformation of the hot-extruded GH4151 alloy. In addition, the step-shaped structures can be observed at grain boundaries, which ensure the low-energy surface state during the DRX process.

Hot Compression Deformation Behavior of Mg-Gd-Y-Zn-Zr Alloy

2014 ◽  
Vol 680 ◽  
pp. 15-22 ◽  
Author(s):  
Guang Lu ◽  
Zhi Ping Xie ◽  
Zhi Min Zhang ◽  
Yong Biao Yang ◽  
Bao Cheng Li
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Great Influence ◽  
Peak Stress ◽  
Maximum Error ◽  
Continuous Dynamic Recrystallization ◽  
Stress Behaviors ◽  
Continuous Dynamic

The deformation behaviors of as-cast Mg-11Gd-2Y-Zn-Zr magnesium alloy were investigated by compression test with Gleeble-1500 thermal simulator at temperature of 623-753K and strain rate of 0.01-0.5 s-1. The flow stress behaviors of the magnesium alloy were carried out at a strain of 0.7. The strain rate and deformation temperature had great influence on the flow stress behaviors. The flow stress increases with increasing strain rate and decreasing temperature. The flow stress has more than one peak stress at a strain rate of 0.5s-1showing continuous dynamic recrystallization (DRX) mechanism, while other flow stresses exhibited only one peak stress indicating discontinuous dynamic recrystallization (DDRX) mechanism. It was also found that the flow stress behavior could be described by the hyperbolic sine constitutive equation, in which the determined average activation energy is 273.426 kJ·mol-1. The maximum error value between calculated value and experimental value is 5.5%. The deformation map was also established, and the best parameter for hot working was found to be 0.1s-1/753k approximately.

Microstructural Evolution and Deformation Mechanisms for Superplasticity of NiAl Intermetallic

2005 ◽  
Vol 475-479 ◽  
pp. 2995-2998
Author(s):  
Jian Ting Guo ◽  
Rong Shi Chen ◽  
Xing Hao Du ◽  
Gu Song Li ◽  
Lan Zhang Zhou
Keyword(s):  
Electron Microscopy ◽  
Microstructural Evolution ◽  
Superplastic Deformation ◽  
Tensile Elongation ◽  
Deformation Mechanisms ◽  
High Angle ◽  
Continuous Dynamic Recrystallization ◽  
Transmission Electron ◽  
Continuous Dynamic ◽  
Temperature Strain

The microstructural evolution during superplastic deformation of the extruded stoichiometric NiAl polycrystals were systemically investigated in various conditions of temperature, strain rate and strain by means of optical microscopy (OM) and transmission electron microscopy (TEM). Consequently, The deformation microstructures corresponding to the large tensile elongation consisted of subgrains, low angle grains as well as high angle grains, which indicated that continuous dynamic recrystallization (CDRX) process was operating during superplastic deformation.

Dynamic Recrystallization of Zircaloy-4 during Working within the Upper α-Range

2004 ◽  
Vol 467-470 ◽  
pp. 1151-1156 ◽  
Author(s):  
Cédric Chauvy ◽  
Pierre Barbéris ◽  
Frank Montheillet
Keyword(s):  
Dynamic Recrystallization ◽  
Large Strain ◽  
Large Angle ◽  
Rate Sensitivity ◽  
Large Strains ◽  
Strain Rates ◽  
Compression Tests ◽  
Continuous Dynamic Recrystallization ◽  
Ebsd Technique ◽  
Continuous Dynamic

Compression tests were used to simulate simple deformation paths within the upper a-range of Zircaloy-4 (i.e. 500°C-750°C). The mechanical behaviour reveals two different domains : at low temperatures and large strain rates, strain hardening takes place before flow softening, whereas this first stage disappears at lower flow stress levels. Strain rate sensitivity and activation energy were determined for both domains. Dynamic recrystallization was investigated using the Electron BackScattering Diffraction (EBSD) technique. It appears that the mechanism involved here is continuous dynamic recrystallization (CDRX), based on the increasing misorientation of subgrain boundaries and their progressive transformation into large angle boundaries. At low strains (e £ 0.3), CDRX kinetics are similar whatever the deformation conditions, while higher temperatures and lower strain rates promote recrystallization at large strains.

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