The role of second phase particles and grain boundaries on recrystallization: Quasi-in situ experiments and modeling in U-10Mo alloy system

2021 ◽  
pp. 153445
Author(s):  
Jacqueline I. Reeve ◽  
Benjamin J. Schuessler ◽  
William E. Frazier ◽  
David P. Field ◽  
Vineet V. Joshi
Keyword(s):  
Grain Boundaries ◽  
Alloy System ◽  
Second Phase ◽  
Second Phase Particles ◽  
In Situ Experiments

Continuous and Discontinuous Recrystallization of 6013 Aluminum Alloy

2013 ◽  
Vol 753 ◽  
pp. 221-224 ◽  
Author(s):  
Krzysztof Sztwiertnia ◽  
Magdalena Bieda ◽  
Anna Korneva
Keyword(s):  
Aluminum Alloy ◽  
Grain Boundaries ◽  
Second Phase ◽  
Sheet Plane ◽  
Temperature Range ◽  
Orientation Mapping ◽  
Second Phase Particles ◽  
The Matrix ◽  
Continuous Recrystallization

In situ orientation mapping using TEM and calorimetric measurements were carried out to investigate the annealing behavior of cold-rolled 6013 aluminum alloy. The recrystallization of the material can be considered to be a number of processes that correspond to two separate stored energy release peaks. In the temperature range of the peak 1, the deformation zones around the large second-phase particles acted as sites for particle-stimulated nucleation. In the matrix, at the same time, some elongation of grains occurred. The elongated matrix grains appeared because of the reduction of the dislocation density and the annihilation of some low-angle grain boundaries between chains of subgrains lying in layers parallel to the sheet plane. The matrix processes in this temperatures range can be considered forms of continuous recrystallization. The matrix high-angle grain boundaries started to migrate at the temperature range of the peak 2. They moved mostly in the direction normal to the sheet plane. Heating of the sample for an appropriate time at those temperatures resulted in the complete discontinuous recrystallization of the material. The recrystallized microstructure was dominated now by elongated grains, which were a few times thicker than those obtained by annealing at the temperatures of the peak 1.

scholarly journals Unravelling the characteristics of Al-alloy corrosion at the atomic to nanometre scale by transmission electron microscopy

2020 ◽  
Vol 326 ◽  
pp. 01007
Author(s):  
Shravan K. Kairy ◽  
Nick Birbilis
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Al Alloy ◽  
Second Phase ◽  
Clear Understanding ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Al Matrix

The localised corrosion associated with Mg2Si in the Al-matrix of an Al-Mg-Si alloy was studied in 0.1 M NaCl at pH 6 by quasi in-situ transmission electron microscopy. Herein, physical imaging of corrosion at the atomic to nanometre scale was performed. Phase transformation and subsequent chemical composition variations associated with the localised corrosion of Mg2Si were studied. It was observed that corrosion initiated upon Mg2Si, often preferentially at the interface with the Al-matrix, and propagated until Mg2Si was completely dealloyed by Mg-dissolution, resulting in an amorphous SiO-rich phase remnant. The SiO-rich remnant became electrochemically inert and did not initiate corrosion in the Al-matrix. This study provides a clear understanding on the localised corrosion of Al-alloys associated with Mg2Si. In addition, the methodology followed in this study can also be applied to understand the role of precipitates and second phase particles in the localised corrosion of Al-alloy systems.

scholarly journals Grain Refinement by Second Phase Particles under Applied Stress in ZK60 Mg Alloy with Y through Phase Field Simulation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1903 ◽  
Author(s):  
Yuhao Song ◽  
Mingtao Wang ◽  
Yaping Zong ◽  
Ri He ◽  
Jianfeng Jin
Keyword(s):  
Grain Refinement ◽  
Applied Stress ◽  
Phase Field ◽  
Phase Particle ◽  
Alloy System ◽  
Second Phase ◽  
Recrystallization Process ◽  
Time Space ◽  
Second Phase Particles ◽  
Zk60 Alloy

Based on the principle of grain refinement caused by the second-phase particles, a phase field model was built to describe the recrystallization process in the ZK60 alloy system with Y added under applied stress between temperatures 573 and 673 K for 140 min duration. The simulation of grain growth with second phase particles and applied stress during annealing process on industrial scale on the condition of real time-space was achieved. Quantitative analysis was carried out and some useful laws were revealed in ZK60 alloy system. The second phase particles had a promoting effect on the grain refinement, however the effect weakened significantly when the content exceeded 1.5%. Our simulation results reveal the existence of a critical range of second phase particle size of 0.3–0.4 μm, within which a microstructure of fine grains can be obtained. Applied stress increased the grain coarsening rate significantly when the stress was more than 135 MPa. The critical size of the second phase particles was 0.4–0.75 μm when the applied stress was 135 MPa. Finally, a microstructure with a grain size of 11.8–13.8 μm on average could be obtained when the second phase particles had a content of 1.5% and a size of 0.4–0.75 μm with an applied stress less than 135 Mpa after 30 min annealing at 573 K.

Effect of mass transport along interfaces and grain boundaries on copper interconnect degradation

2004 ◽  
Vol 812 ◽  
Author(s):  
Ehrenfried Zschech ◽  
Moritz A. Meyer ◽  
Eckhard Langer
Keyword(s):  
Mass Transport ◽  
Grain Boundaries ◽  
Void Formation ◽  
Degradation Process ◽  
Copper Interconnects ◽  
Second Phase ◽  
Copper Interconnect ◽  
Void Evolution ◽  
Two Phases

AbstractIn-situ SEM electromigration studies were performed at fully embedded via/line interconnect structures to visualize the time-dependent void evolution in inlaid copper interconnects. Void formation, growth and movement, and consequently interconnect degradation, depend on both interface bonding and copper microstructure. Two phases are distinguished for the electromigration-induced interconnect degradation process: In the first phase, agglomerations of vacancies and voids are formed at interfaces and grain boundaries, and voids move along weak interfaces. In the second phase of the degradation process, they merge into a larger void which subsequently grows into the via and eventually causes the interconnect failure. Void movement along the copper line and void growth in the via are discontinuous processes, whereas their step-like behavior is caused by the copper microstructure. Directed mass transport along inner surfaces depends strongly on the crystallographic orientation of the copper grains. Electromigration lifetime can be drastically increased by changing the copper/capping layer interface. Both an additional CoWP coating and a local copper alloying with aluminum increase the bonding strength of the top interface of the copper interconnect line, and consequently, electromigration-induced mass transport and degradation processes are reduced significantly.

Role of second-phase particles in the microstructural evolution and mechanical properties of extruded Mg-Gd-Y-Ag-Zr alloys

2020 ◽  
Vol 24 ◽  
pp. 100956
Author(s):  
Fan Zhang ◽  
Yafei Wang ◽  
Yunbiao Duan ◽  
Kaijun Wang ◽  
Yutian Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Evolution ◽  
Second Phase ◽  
Second Phase Particles ◽  
Zr Alloys

Cavity of Al-Cu-Mg Alloy during Superplastic Deformation

2007 ◽  
Vol 551-552 ◽  
pp. 645-650
Author(s):  
Min Wang ◽  
Hong Zhen Guo ◽  
Y.J. Liu
Keyword(s):  
Strain Rate ◽  
Grain Boundaries ◽  
Superplastic Deformation ◽  
Room Temperature ◽  
Mg Alloy ◽  
Deformation Condition ◽  
Second Phase ◽  
Rate Condition ◽  
Second Phase Particles ◽  
Strain Rate Condition

According to the characteristic of appearing cavitation in the metals during superplastic deformation, the influence of strain rate on cavity evolvement, the influence of cavity on superplastic deformation capability, and the formation, development process of cavity were investigated for Al-Cu-Mg alloy (i.e. coarse–grained LY12). The results show that: ①The pore nucleation occurs not only at triangle grain boundaries, but also along nearby the second phase particles, and even within grains. The cavities at the triangle grain boundaries are present in V-shape, others near the second phase particles and within grains are present in O-shape. These cavities may result from disharmony slippage of grain boundaries. ②The tendency of cavity development decreases with increasing of strain-rate. In lower strain-rate condition, though Al-Cu-Mg alloy has better superplasticity, many big cavities in the specimen may reduce the room temperature properties of the alloy. In higher strain-rate condition, Al-Cu-Mg alloy has certain superplasticity and room temperature properties as well as few cavities forming. By analyzing, viscous layer on grain boundaries is very thin and grain sizes can be refined during their extruding and rotating each other in higher strain-rate superplastic deformation condition. ③Growth and coalescence of cavity are the main reason of the superplastic fracture of Al-Cu-Mg alloy. And small and a certain amount of cavities with dispersion and independence state are very useful to crystal boundary slippage.

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