Deformation of fine-grained alumina by grain boundary sliding accommodated by slip

2003 ◽  
Vol 51 (12) ◽  
pp. 3617-3634 ◽  
Author(s):  
Oscar A. Ruano ◽  
Jeffrey Wadsworth ◽  
Oleg D. Sherby
Keyword(s):  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Fine Grained ◽  
Boundary Sliding

Role of Vacancies and Solute Atoms on Grain Boundary Sliding

1999 ◽  
Vol 601 ◽  
Author(s):  
J.S. Vetrano ◽  
C.H. Henager ◽  
E.P. Simonen
Keyword(s):  
Grain Boundary ◽  
Solute Atom ◽  
Vacancy Concentration ◽  
Grain Boundary Sliding ◽  
Fine Grained ◽  
Grain Boundary Plane ◽  
Transmission Electron ◽  
Boundary Sliding ◽  
Solute Atoms

AbstractIt is necessary for grain boundary dislocations to slide and climb during the grain boundary sliding process that dominates fine-grained superplastic deformation. The process of climb requires either an influx of vacancies to the grain boundary plane or a local generation of vacancies. Transmission electron microscopy (TEM) observations of grain boundaries in superplastically deformed Al-Mg-Mn alloys quenched under load from the deformation temperature have revealed the presence of nano-scale cavities resulting from a localized supersaturation of vacancies at the grain boundary. Compositional measurements along interfaces have also shown an effect of solute atoms on the local structure. This is shown to result from a coupling of vacancy and solute atom flows during deformation and quenching. Calculations of the localized vacancy concentration indicate that the supersaturation along the grain boundary can be as much as a factor often. The effects of the local supersaturation and solute atom movement on deformation rates and cavity nucleation and growth will be discussed.

Deformation Behavior of Fine Grained Al-Mg Alloy under Biaxial Stress

2006 ◽  
Vol 503-504 ◽  
pp. 475-480 ◽  
Author(s):  
Masafumi Noda ◽  
Kunio Funami
Keyword(s):  
Grain Boundary ◽  
Tensile Deformation ◽  
Grain Boundary Sliding ◽  
Biaxial Stress ◽  
Mg Alloy ◽  
Strain Rates ◽  
Fine Grained ◽  
Biaxial Tensile ◽  
Wide Range ◽  
Boundary Sliding

The grain boundary sliding and the formation of slipped bands and cavitations during biaxial tensile deformation were examined in fine grained Al-Mg alloy. Biaxial tensile testing was conducted with cruciform specimens at initial strain rates of 10-4 to 101s-1. It was found that at the same equivalent strain conditions, the number of cavities under biaxial tension is significantly greater than that under uniaxial tension. A greater prevalence of slipped bands and grain separations were clearly observed under biaxial stress than under uniaxial stress. It was suggested that development of slipped bands resulted from the formation of elongated cavities and multiple deformed bands under biaxial stress. Additionally, the m-value under biaxial stress remained at about 0.3 over a wide range of strain rates. The effects of grain separation and formation of cavities were related to the motion of grain boundary sliding, grain size and loading conditions.

High Temperature Mechanical Loss Spectrum of 3Y-TZP Zirconia Reinforced with Carbon Nanotubes or Silicon Carbide Whiskers

2008 ◽  
Vol 137 ◽  
pp. 29-34 ◽  
Author(s):  
Claudia Ionascu ◽  
Robert Schaller
Keyword(s):  
Carbon Nanotubes ◽  
Silicon Carbide ◽  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Mechanical Spectroscopy ◽  
Multiwalled Carbon ◽  
Fine Grained ◽  
Silicon Carbide Whiskers ◽  
Boundary Sliding

High temperature plasticity of fine-grained ceramics (ZrO2, Al2O3, etc) is usually associated with a grain boundary sliding process. The aim of the present research is then to improve the high-temperature mechanical strength of polycrystalline zirconia (3Y-TZP) through the insertion of multiwalled carbon nanotubes (CNTs) or silicon carbide whiskers (SiCw), which are susceptible to pin the grain boundaries. The effect of these nano-sized particles on grain boundary sliding has been studied by mechanical spectroscopy.

Texture Change during Superplastic Deformation in Fine-Grained Magnesium Alloys

2016 ◽  
Vol 838-839 ◽  
pp. 59-65 ◽  
Author(s):  
Hiroyuki Watanabe ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Grain Boundary ◽  
Magnesium Alloys ◽  
Superplastic Deformation ◽  
Longitudinal Direction ◽  
Grain Boundary Sliding ◽  
Dislocation Slip ◽  
Grain Rotation ◽  
Fine Grained ◽  
Texture Change ◽  
Boundary Sliding

Texture change during superplastic deformation was examined and compared in two magnesium alloys with different chemical composition. These alloys were extruded to refine the microstructure. The pre-existing basal texture of both alloys became slightly more random within the bulk probably owing to grain boundary sliding and the accompanying grain rotation. However, the texture changes differed between tensile and compressive deformation along the extrusion (longitudinal) direction. This fact suggests that dislocation slip is important in superplastic deformation. It was concluded that dislocation slip acts primarily as an accommodation mechanism for grain boundary sliding.

Sign in / Sign up

Export Citation Format

Share Document