Optimization of the grain boundary character distribution of pure copper by low-strain thermomechanical processing

2020 ◽  
Vol 111 (8) ◽  
pp. 668-675
Author(s):  
Kunpeng Zhao ◽  
Ziyun Chen ◽  
Yuan Qin ◽  
Xinye Yang ◽  
Ming Huang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Thermomechanical Processing ◽  
Pure Copper ◽  
Grain Boundary Character Distribution ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

Evolution of Grain Boundary Character Distribution in Pure Copper during Low-Strain Thermomechanical Processing

2019 ◽  
Vol 944 ◽  
pp. 229-236
Author(s):  
Guo Qing Wu ◽  
Zi Yun Chen ◽  
Ming Huang ◽  
Yuan Qin ◽  
Alimjan Ablat ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Thermomechanical Processing ◽  
Boundary Migration ◽  
Pure Copper ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Engineering ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

In order to get optimal grain boundary character distribution (GBCD) and grain boundary properties, thermomechanical processing (TMP) is usually adopted in grain boundary engineering. However, the mechanism behind the TMP treatments and GBCD optimization is still unclear. The present study has conducted a series experiments involving low-strain TMPs to study the relationship between TMP parameters and the behind microstructural evolution. The experimental results indicate that in the scope of low-strain TMP, strain induced boundary migration (SIBM) is the most effective process for GBCD optimization. Besides, SIBM and grain growth would gradually transfer to recrystallization with the increase of pre-deformation level and annealing temperature. Further quasi in-situ EBSD results infer that SBIM is activated locally in some region with high stored energy, and further gradual initiation of SIBM from one region to another contributes to the gradual increase of special boundaries with annealing time.

Optimization of the grain boundary character distribution of pure copper by low-strain thermomechanical processing

2020 ◽  
Vol 111 (8) ◽  
pp. 668-675
Author(s):  
Ming Huang ◽  
Kunpeng Zhao ◽  
Ziyun Chen ◽  
Yuan Qin ◽  
Xinye Yang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Migration ◽  
Pure Copper ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Migration ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

Abstract Although thermomechanical processing has been widely used in grain boundary engineering, the relationship between thermomechanical parameters and grain boundary character distribution is still not well understood. In the present study, electron backscatter diffraction was used to study the grain boundary character distribution in pure copper after lowstrain thermomechanical treatments. It was found that the low-R coincidence site lattice frequency and grain size decreases in the following sequence, 10% compression > 15% compression > 5% compression, except for 700 0C. During thermomechanical treatments of copper, strain-induced grain boundary migration and grain growth may occur during annealing of 5% compressed copper, and recrystallization dominates during annealing of 15% compressed copper, while the annealing mechanism of 10% compressed copper changes from strain-induced grain boundary migration and grain growth to recrystallization when the annealing temperature exceeds 600 0C. The results indicated that during single-step low-strain thermomechanical treatments, straininduced grain boundary migration and grain growth would gradually change to recrystallization with the increase of pre-deformation level and annealing temperature. Among the three mechanisms, strain-induced grain boundary migration seems to be more effective than recrystallization and grain growth in the optimization of grain boundary character distribution, and it is suggested that this is due to the high boundary migration rate of strain-induced grain boundary migration.

scholarly journals Influence of Processing Method on the Grain Boundary Character Distribution and Network Connectivity

1999 ◽  
Vol 586 ◽  
Author(s):  
Adam J. Schwartz ◽  
Mukul Kumar ◽  
Wayne E. King
Keyword(s):  
Grain Boundary ◽  
Annealing Temperature ◽  
Thermomechanical Processing ◽  
Processing Method ◽  
Grain Boundary Character Distribution ◽  
Deformation Path ◽  
Inconel 600 ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

ABSTRACTThere exists a growing body of literature that correlates the fraction of “special” boundaries in a microstructure, as described by the Coincident Site Lattice Model, to properties such as corrosion resistance, intergranular stress corrosion cracking, creep, etc. Several studies suggest that the grain boundary character distribution (GBCD), which is defined in terms of the relative fractions of “special” and “random” grain boundaries, can be manipulated through thermomechanical processing. This investigation evaluates the influence of specific thermomechanical processing methods on the resulting GBCD in FCC materials such as oxygenfree electronic (ofe) copper and Inconel 600. We also demonstrate that the primary effect of thermomechanical processing is to reduce or break the connectivity of the random grain boundary network. Samples of ofe Cu were subjected to a minimum of three different deformation paths to evaluate the influence of deformation path on the resulting GBCD. These include: rolling to 82% reduction in thickness, compression to 82% strain, repeated compression to 20% strain followed by annealing. In addition, the influence of annealing temperature was probed by applying, for each of the processes, three different annealing temperatures of 400, 560, and 800°C. The observations obtained from automated electron backscatter diffraction (EBSD) characterization of the microstructure are discussed in terms of deformation path, annealing temperature, and processing method. Results are compared to previous reports on strainannealed ofe Cu and sequential processed Inconel 600. These results demonstrate that among the processes considered, sequential processing is the most effective method to disrupt the random grain boundary network and improve the GBCD.

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