Influence of Symmetrical <10‾10> High-Angle Tilt Grain Boundaries on the Local Mechanical Properties of Magnesium Bicrystals

2020 ◽  
Author(s):  
Jann-Erik Brandenburg ◽  
J. Seo ◽  
Dmitri A. Molodov ◽  
Sadahiro Tsurekawa
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
High Angle

Mechanical Properties of an Accumulative Roll Bonded Aluminium Alloy Composite

2009 ◽  
Vol 618-619 ◽  
pp. 551-554 ◽  
Author(s):  
O. Al-Buhamad ◽  
M. Zakaria Quadir ◽  
Michael Ferry
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Annealing Temperature ◽  
Sheet Material ◽  
Commercial Purity ◽  
Alloy Composite ◽  
High Angle ◽  
Roll Bonding ◽  
Fine Grained ◽  
Strength And Ductility

A multilayered sheet composite of commercial purity Al and Al-0.3%Sc alloys was produced by accumulative roll bonding. The final sheet material consisted of 64 ultra fine grained layers, each of ~7.8mm in thickness. The as-deformed material was annealed at temperatures ranging from 250 to 350°C to study the changes in microstructure and their associated influence on mechanical properties. The as-deformed structures largely comprised of high angle grain boundaries in the Al layers and low angle grain boundaries in the Al(Sc) layers. During annealing, the structures in the Al(Sc) layers remained unaltered, whereas the Al layers recrystallized rapidly to the full layer thickness. The mechanical properties of the Al-Al(Sc) composite were measured and found to be unique in strength and ductility with annealing temperature having a significant influence on these properties.

scholarly journals Analysis of Microstructure and Mechanical Properties Changes in AA1050 Aluminum Subjected to ECAP and KoBo Processes / Analiza Zmian Mikrostruktury I Własności Mechanicznych Aluminium AA1050 Po Procesie ECAP I KoBo

2015 ◽  
Vol 60 (4) ◽  
pp. 3063-3068 ◽  
Author(s):  
R. Bogucki ◽  
K. Sulikowska ◽  
M. Bieda ◽  
P. Ostachowski ◽  
K. Sztwiertnia
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Grain Boundaries ◽  
Equal Channel Angular Pressing ◽  
High Angle ◽  
Electron Backscattered Diffraction ◽  
Deformation Degree ◽  
Angular Pressing ◽  
Ecap Process ◽  
Processed Sample

Analysis of the results of the microstructure and the mechanical properties change in AA1050 aluminum alloy of technical purity processed using ECAP (Equal Channel Angular Pressing) and KoBo deformation methods are presented in the paper.. ECAP process was performed according to Bc scheme in the range from 1 up to 10 passes. Changes of microstructure were analyzed using scanning electrone microscope equipped with electron backscattered diffraction (EBSD) system. Microstructure and fraction of high-angle grain boundaries in KoBo processed samples were similar to those observed in ECAP processed samples after four passes. The most significant microstructure refinement was observed in ECAP processed sample submitted to 10 passes. In ECAP method the systematic increase of mechanical properties was observed along with increase of deformation degree.

Study on Mechanical Properties Anisotropy of X80 Pipeline Steel

2013 ◽  
Vol 803 ◽  
pp. 413-418
Author(s):  
Qiang Duan ◽  
Jun Yan ◽  
Guo Hui Zhu ◽  
Qing Wu Cai
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Impact Toughness ◽  
Crack Propagation ◽  
Grain Boundaries ◽  
Pipeline Steel ◽  
Rolling Direction ◽  
High Angle ◽  
X80 Pipeline Steel ◽  
Effective Grain Size

The microstructure of X80 pipeline steel in different directions were observed by SEM technique and its effective grain size and misorientation were statistically analyzed by EBSD system. Based on these results, the mechanical properties at 0°, 45° and 90° to the rolling direction of X80 pipeline steel were studied. The results show that, owing to finer grain size and less low-angle grain boundaries, strengths and impact toughness of X80 pipeline steel at 90° direction are optimal. While the pipeline steel possesses finer grain size, more high-angle grain boundaries and less low-angle grain boundaries, the crack propagation is effectively suppressed, then its impact toughness is improved.

Microstructure Evolution and Mechanical Properties of an AZ61 Mg Alloy through Cyclic Extrusion Compression

2007 ◽  
Vol 546-549 ◽  
pp. 253-256 ◽  
Author(s):  
Lu Jun Zhang ◽  
Qu Dong Wang ◽  
Yong Jun Chen ◽  
Jin Bao Lin
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Microstructure Evolution ◽  
Dynamic Recovery ◽  
Mg Alloy ◽  
High Angle ◽  
Initial Stage ◽  
Cyclic Extrusion Compression ◽  
Continuous Dynamic ◽  
Az61 Mg Alloy

Microstructure evolution and mechanical properties of an AZ61 Mg alloy processed by cyclic extrusion compression were investigated. It is shown that CEC process may be applied successfully to AZ61 Mg alloys, and this leads to excellent grain refinement with grain size of ~0.8μm after 15 passes at 573K and to significant improvements in yield strength, ductility and hardness of AZ61 materials with slight compressive strength decreases. Dislocations were induced at initial stage of CEC process, and with increased deformation, tangled dislocations developed to form dislocation boundaries and subgrain boundaries, and then evolved into low angle grain boundaries (LAGBs) and high angle grain boundaries (HAGBs) which was regarded as continuous dynamic recovery and recrystallization (CDRR).

Measurement of the Displacement Across a Coincidence Grain Boundary

1977 ◽  
Vol 35 ◽  
pp. 124-125
Author(s):  
J. W. Matthews ◽  
W. M. Stobbs
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stacking Fault ◽  
The Other ◽  
Measuring Technique ◽  
High Angle ◽  
Twin Boundaries ◽  
Rigid Displacement ◽  
Cubic Crystals ◽  
Lattice Displacement

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

Observations of dislocation interactions with recrystallized grain boundaries

1988 ◽  
Vol 46 ◽  
pp. 628-629
Author(s):  
C. W. Price
Keyword(s):  
Dislocation Density ◽  
Grain Boundary ◽  
Strain Rate ◽  
Grain Boundaries ◽  
Dislocation Structure ◽  
Hot Deformation ◽  
Static Recrystallization ◽  
High Dislocation Density ◽  
High Angle ◽  
Dislocation Interactions

Little evidence exists on the interaction of individual dislocations with recrystallized grain boundaries, primarily because of the severely overlapping contrast of the high dislocation density usually present during recrystallization. Interesting evidence of such interaction, Fig. 1, was discovered during examination of some old work on the hot deformation of Al-4.64 Cu. The specimen was deformed in a programmable thermomechanical instrument at 527 C and a strain rate of 25 cm/cm/s to a strain of 0.7. Static recrystallization occurred during a post anneal of 23 s also at 527 C. The figure shows evidence of dissociation of a subboundary at an intersection with a recrystallized high-angle grain boundary. At least one set of dislocations appears to be out of contrast in Fig. 1, and a grainboundary precipitate also is visible. Unfortunately, only subgrain sizes were of interest at the time the micrograph was recorded, and no attempt was made to analyze the dislocation structure.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

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