scholarly journals Shear-coupled migration of grain boundaries: the key missing link in the mechanical behavior of small-grained metals?

2021 ◽  
Vol 22 (S3) ◽  
pp. 1-16
Author(s):  
Romain Gautier ◽  
Armin Rajabzadeh ◽  
Melvyn Larranaga ◽  
Nicolas Combe ◽  
Frédéric Mompiou ◽  
...  
2012 ◽  
pp. 13-24 ◽  
Author(s):  
Patrick Villechaise ◽  
Jonathan Cormier ◽  
Thomas Billot ◽  
José Mendez

2005 ◽  
Vol 51 (174) ◽  
pp. 377-382 ◽  
Author(s):  
Min Song ◽  
Ian Baker ◽  
David M. Cole

AbstractThe mechanical behavior and microstructural evolution of laboratory-prepared, particle-free fresh-water ice and ice with 1 wt.% (~0.43 vol.%) silt-sized particles were investigated under creep with a stress level of 1.45 MPa at −10°C. The particles were present both within the grains and along the grain boundaries. The creep rates of specimens with particles were always higher than those of particle-free ice. Dynamic recrystallization occurred for both sets of specimens, with new grains nucleating along grain boundaries in the early stages of creep. The ice with particles showed a higher nucleation rate. This resulted in a smaller average grain-size for the ice with particles after a given creep strain. Fabric studies indicated that ice with particles showed a more random orientation of c axes after creep to ~10% strain than the particle-free ice.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1040-1046 ◽  
Author(s):  
CHIH-CHIANG FU ◽  
JASON SHIAN-CHING JANG ◽  
I-SUI LEE ◽  
HUEI-SEN WANG

The effect of strain rate and temperature on the mechanical behavior of the Ni -18 Si -3.0 Nb -1.0 Cr -0.2 B alloy was investigated by atmosphere-controlled tensile testing in vacuum and air atmosphere at different strain rates and different temperatures. The results reveal that the Ni -18 Si -3.0 Nb -1.0 Cr -0.2 B alloy exhibits ductile mechanical behavior (UTS > 1200 MPa, ε > 8%) at room temperature under different atmosphere conditions. In addition, both of the ultimate tensile strength and elongation exhibit quite insensitive response with respect to the loading strain rate when tests are held at temperatures below 973K. The elongation of the samples tested in vacuum and air for the Ni -18 Si -3 Nb -1 Cr -0.2 B alloy exhibits a significantly increase with temperature from 973K to 1073K. In addition, all fracture surfaces tested at 1073K in vacuum and air atmosphere presents a typical ductile fracture surface, a fully dimpled fracture pattern. The fact of increasing in elongation at high temperature (1073K) is suggested to be attributed by the dynamic recrystallization that occurs preferentially around the dispersion phase or grain boundaries and so as to enhance the ductility by reducing the stress concentration at or near grain boundaries.


1981 ◽  
Vol 12 ◽  
Author(s):  
M.F.X. Gigliotti ◽  
M. R. Jackson ◽  
S. W. Yang ◽  
M. F. Henry ◽  
D. A. Woodford

Superalloy eutectics strengthened with monocarbide whiskers are highly anisotropic in strength. Mechanical behavior transverse to the growth axis is governed largely by the fracture resistance of the matrix grain boundaries. While the matrices of these eutectics are essentially columnar grained superalloys, there are significant differences between d.s. superalloys and superalloy-monocarbide eutectics. These differences arise, in part from different solidification processes and from the alloying limitations in eutectic systems.


2011 ◽  
Vol 25 (12) ◽  
pp. 1689-1700 ◽  
Author(s):  
QIHENG TANG ◽  
TIANYONG YANG

The indentation simulation of the nanocrystalline Ni is carried out by molecular dynamics technique (MD) to study the mechanical behavior at nanometer scales. The sphere indenter is used, and simulation sample with three grains and two grain boundaries is adopted. The strength of nanocrystalline is studied as indenter is set at grain boundary and grain, respectively. Some defects such as dislocations or slipping deformation are observed. It is found that dislocations are emitted from the grain boundary or the sample surface. The temperature distribution of local region around indenter is analyzed and it can explain our MD simulation results.


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