A model for high temperature deformation based on dislocation dynamics, rate theory and a periodic internal stress

1970 ◽  
Vol 18 (5) ◽  
pp. 511-517 ◽  
Author(s):  
M.J. Luton ◽  
J.J. Jonas
Keyword(s):  
High Temperature ◽  
Internal Stress ◽  
Dislocation Dynamics ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Rate Theory

Comparison of Internal and Residual Stresses Measured by Strain-Dip Test and XRD during High Temperature Deformation of Al-Mg Solid Solutions

2013 ◽  
Vol 768-769 ◽  
pp. 351-357
Author(s):  
H. Sato ◽  
Y. Enomoto ◽  
K. Omote ◽  
S.I. Tanaka
Keyword(s):  
High Temperature ◽  
Residual Stresses ◽  
Internal Stress ◽  
Applied Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Condition ◽  
Internal Stresses ◽  
Principal Stresses ◽  
Dip Test

Creep behavior of solid solution alloys are reasonably explained by concepts of the “internal and effective stress of high temperature deformation”. The internal stress is considered to be brought by formation of dislocation substructures, and the dislocation structures should have caused long range stress filed in interior of materials. Thus, residual stresses should also be brought by the same origin. In this paper, measurements of the residual stresses after creep deformation by 2D-Xray method are attempt, and the stresses are compared with so-called the “internal stress of high temperature deformation” measured by strain-dip stress-transient test. Although, the stress tensor depends on the deformation condition, the relation with the applied stress show complex manner at a glance. The maximum principal stresses, however, show relatively smaller than the applied stress, and fairly agree with that measured by strain-dip stress-transient technique. Importance of further considerations of the origin of so-called internal stresses is suggested.

Precipitate Shearing, Fault Energies, and Solute Segregation to Planar Faults in Ni-, CoNi-, and Co-Base Superalloys

2021 ◽  
Vol 51 (1) ◽  
pp. 209-240
Author(s):  
Y.M. Eggeler ◽  
K.V. Vamsi ◽  
T.M. Pollock
Keyword(s):  
High Temperature ◽  
Dislocation Dynamics ◽  
Deformation Mechanisms ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Two Phase ◽  
Planar Defects ◽  
Planar Fault ◽  
Operating Environments ◽  
Chemical Segregation

The mechanical properties of superalloys are strongly governed by the resistance to shearing of ordered precipitates by dislocations. In the operating environments of superalloys, the stresses and temperatures present during thermomechanical loading influence the dislocation shearing dynamics, which involve diffusion and segregation processes that result in a diverse array of planar defects in the ordered L12 γ′ precipitate phase. This review discusses the current understanding of high-temperature deformation mechanisms of γ′ precipitates in two-phase Ni-, Co-, and CoNi-base superalloys. The sensitivity of planar fault energies to chemical composition results in a variety of unique deformation mechanisms, and methods to determine fault energies are therefore reviewed. The degree of chemical segregation in the vicinity of planar defects reveals an apparent phase transformation within the parent γ′ phase. The kinetics of segregation to linear and planar defects play a significant role in high-temperature properties. Understanding and controlling fault energies and the associated dislocation dynamics provide a new pathway for the design of superalloys with exceptional properties.

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