A New Interpretation of Stress Relaxations in Ni3(Al,Hf) Single Crystals.

1994 ◽  
Vol 364 ◽  
Author(s):  
J. Bonneville ◽  
P. Spätig ◽  
J.-L. Martin
Keyword(s):  
Dislocation Density ◽  
Strain Hardening ◽  
Single Crystals ◽  
Mobile Dislocation ◽  
Mobile Dislocation Density ◽  
Flow Strength ◽  
Preliminary Results ◽  
Strain Stress ◽  
New Interpretation ◽  
Strain Hardening Rate

AbstractA technique of repeated stress relaxations is used to characterise the strain hardening rate (K) and the mobile dislocation density (ρm) in the flow strength anomaly domain of Ni3(Al,Hf) single crystals. It is shown that there is no independent means for measuring both effects but that reasonable assumptions about the strain hardening rate lead to determine the variation of ρm during relaxation. Preliminary results indicate that during relaxation ρm decreases more rapidly with strain (stress) when the temperature is raised.

The creation rate of mobile dislocation density in a creep experiment

1986 ◽  
Vol 20 (8) ◽  
pp. 1075-1078 ◽  
Author(s):  
J.A. Montemayor-Aldrete ◽  
J. Soullard ◽  
R. Gómez-Ramírez ◽  
A. Calles
Keyword(s):  
Dislocation Density ◽  
Mobile Dislocation ◽  
Mobile Dislocation Density ◽  
Creep Experiment ◽  
The Creation ◽  
Creation Rate

The Influence of Mobile Dislocation Density on the Fracture Toughness of B2-Based Ni-Fe-Al Alloys

1994 ◽  
Vol 350 ◽  
Author(s):  
A. Misra ◽  
R. D. Noebe ◽  
R. Gibala
Keyword(s):  
Fracture Toughness ◽  
Dislocation Density ◽  
Tensile Ductility ◽  
Growth Direction ◽  
Mobile Dislocation ◽  
Second Phase ◽  
Mobile Dislocation Density ◽  
Dislocation Generation ◽  
Multiphase Materials ◽  
Β Phase

AbstractThe deformation and fracture behaviors of two directionally solidified multi-phase Ni-Fe-Al ordered alloys were investigated. One alloy consisted of continuous β+γ lamellae with fine γ precipitates within the γ phase. The NiAl-based β phase of this alloy exhibited <100> slip even when deformed parallel to the [001] growth direction. This material exhibited an initiation fracture toughness of ∼ 30 MPa √m and tensile ductility of 10%. The second alloy consisted of aligned but discontinuous γ lamellae within a continuous β phase. Again, the γ phase contained γ precipitates, but unlike the previous alloy, the β phase also contained a fine dispersion of bcc precipitates due to spinodal decomposition. The β phase of this alloy deformed by <111> slip. This four-phase alloy exhibited a fracture toughness of ∼ 21 MPa √m and tensile ductility of 2%. Observations of the plastic zone in both alloys indicated significant plasticity in the β phase due to easy slip transfer from the ductile second phase. The enhanced fracture resistance of these multiphase materials compared to single phase β alloys is attributed in large part to intrinsic toughening of the β phase by an increased mobile dislocation density due to efficient dislocation generation from the β/γ interfaces.

A consideration of mobile dislocation density

1978 ◽  
Vol 12 (9) ◽  
pp. 753-757 ◽  
Author(s):  
S. Raghuraman ◽  
R.J. Arsenault
Keyword(s):  
Dislocation Density ◽  
Mobile Dislocation ◽  
Mobile Dislocation Density
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