Rearrangement of fatigue dislocation structure in copper single crystals associated with reduction in the plastic strain amplitude

2002 ◽  
Vol 82 (7) ◽  
pp. 1317-1330 ◽  
Author(s):  
C. Watanabe ◽  
K. Kanmuri ◽  
M. Kato ◽  
S. Onaka ◽  
T. Fujii
Keyword(s):  
Plastic Strain ◽  
Single Crystals ◽  
Strain Amplitude ◽  
Dislocation Structure ◽  
Plastic Strain Amplitude ◽  
Copper Single Crystals

Cyclic Deformation Behavior of Ni3Ge Single Crystals At Room Temperature

1984 ◽  
Vol 39 ◽  
Author(s):  
Han-Ryong Pak ◽  
Leih-Ming Hsiung ◽  
Masaharu Kato
Keyword(s):  
Plastic Strain ◽  
Single Crystals ◽  
Strain Amplitude ◽  
Cyclic Deformation ◽  
Room Temperature ◽  
Stress Amplitude ◽  
Plastic Strain Amplitude ◽  
Total Strain Amplitude ◽  
Screw Dislocations ◽  
Stress Asymmetry

ABSTRACTFully reversed strain-controlled, tension-compression tests were performed at room temperature to study cyclic-deformation properties of Ni3Ge single crystals. The cyclic deformation is performed with the stress axis parallel to the [1 1.94 2.69] direction at a strain rate of 1.0 × 10-4 s-1 and at a total-strain amplitude between 5.0 × 10-4 and 1.5 × 10-3. Cyclic strain-hardening occurs to saturation over the range of the employed strain amplitudes. The cyclic-stress amplitude is higher in compression than in tension at a plastic-strain amplitude larger than 1 × 10-5 where screw dislocations are operative. This stress asymmetry becomes more prominent (i.e., the mean stress-amplitude becomes larger in magnitude) as the plastic-strain amplitude becomes larger. At a plastic-strain amplitude less than 1 × 10-5 where edge dislocations are operative, the stress amplitude is symmetric. A similar stress asymmetry is also observed for monotonic flow stress. The cyclic hardening is explained by considering an interaction between the screw dislocations.

Cyclic Deformation of Al-Mg Single Crystals with a Single Slip Orientation

2007 ◽  
Vol 561-565 ◽  
pp. 2213-2216
Author(s):  
Toshiyuki Fujii ◽  
Shizuma Uju ◽  
Chihiro Watanabe ◽  
Susumu Onaka ◽  
Masaharu Kato
Keyword(s):  
Plastic Strain ◽  
Single Crystals ◽  
Strain Amplitude ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Plastic Strain Amplitude ◽  
Solid Solution Hardening ◽  
Plateau Stress ◽  
Single Slip

Fully reversed tension-compression fatigue tests were performed on solid-solutioned Al-0.7mass%Mg single crystals with a single slip orientation under constant plastic-strain amplitudes. Dislocation microstructures were quantitatively examined by transmission electron microscopy. The cyclic stress–strain curve (CSSC) exhibited three distinct regions with a short plateau region in the intermediate plastic-strain amplitude range, and the plateau stress was 26MPa. Characteristic microstructures were developed corresponding to the three regions in the CSSC. Vein structure was observed at the low strain-amplitude region. In the plateau regime, the persistent slip bands (PSBs) were observed. Labyrinth structure was also observed at the higher strain-amplitude region. The plateau stress, the cyclic flow stress of PSBs, can be explained by considering not only the Orowan bowing stress and the dipole passing stress of screw dislocations but also solid-solution hardening by Mg atoms.

Sign in / Sign up

Export Citation Format

Share Document