Effects of prior plastic deformation on the martensitic transformation in oriented single crystals of Au-47.5 at.% Cd

1973 ◽  
Vol 8 (11) ◽  
pp. 1616-1624
Author(s):  
M. L. Green ◽  
M. S. Wald ◽  
K. Mukherjee
Keyword(s):  
Plastic Deformation ◽  
Martensitic Transformation ◽  
Single Crystals ◽  
Prior Plastic Deformation

Effect of Plastic Deformation on the Isothermal FCC/HCP Phase Transformation during Aging of Co-27Cr-5Mo-0.05C Alloy

2007 ◽  
Vol 560 ◽  
pp. 23-28
Author(s):  
A. Mani-Medrano ◽  
Armando Salinas-Rodríguez
Keyword(s):  
Plastic Deformation ◽  
Martensitic Transformation ◽  
Tensile Deformation ◽  
Internal Stresses ◽  
X Ray Diffraction ◽  
Thermally Activated ◽  
Prior Plastic Deformation ◽  
Last Stage ◽  
Isothermal Martensitic Transformation

The effects of tensile deformation on the amount of hcp phase formed during a 3 hour isothermal aging at 800 °C is studied using in-situ X-ray diffraction and scanning electron microscopy. It is shown that the start of the isothermal martensitic transformation during aging of this material is delayed by prior plastic deformation. Nevertheless, the total amount of hcp phase present in the microstructure at the beginning of aging increases at a continuously decreasing rate due to stress-assisted transformation. This behavior is attributed to the relieving of internal stresses produced by plastic deformation prior to aging. Finally, during the last stage of aging, the amount of hcp phase in the microstructure increases as a result of isothermal martensitic transformation. It is suggested that the presence of mechanically-induced hcp phase during aging inhibits the thermally activated nucleation process that leads to the isothermal martensitic transformation.

The fold-sector dependence of plastic deformation modes in polyethylene single crystals

1974 ◽  
Vol 341 (1624) ◽  
pp. 75-90 ◽  
Keyword(s):  
Plastic Deformation ◽  
Martensitic Transformation ◽  
Single Crystals ◽  
Tensile Axis ◽  
Deformation Behaviour ◽  
Chain Molecules ◽  
Deformation Processes ◽  
Deformation Modes ◽  
Marked Dependence

It is generally recognized that there are significant differences in the geometry of folded chain molecules from sector to sector in diamond shaped polyethylene single crystals. Single crystals of this type were deformed on a Mylar substrate in order to determine the effect of changes in fold geometry on the operative deformation processes. A marked dependence of the operation of stress induced slip, twinning and martensitic transformation with fold geometry was observed. The differences in the deformation behaviour of adjacent fold sectors could be explained simply in terms of the orientation of the molecular folds with respect to the tensile axis.

Investigation of shock-wave deformation history from recovered structure

1986 ◽  
Vol 44 ◽  
pp. 434-435
Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Shock Waves ◽  
Shock Front ◽  
Single Crystals ◽  
Residual Deformation ◽  
Deformation Structure ◽  
Deformation History ◽  
Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

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