High-Temperature Creep of Nb-Al-V Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
Tie-Sheng Rong ◽  
Mark Aindow
Keyword(s):  
Activation Energy ◽  
Steady State ◽  
High Temperature ◽  
Creep Deformation ◽  
Steady State Creep ◽  
High Temperature Creep ◽  
Creep Mechanisms ◽  
Creep Curves ◽  
Rapid Transition ◽  
A15 Phase

ABSTRACTNb-15A1-20V alloys with about 45% by volume of an A15 phase in a B2 matrix have been subjected to creep deformation at temperatures between 1000°C and 1200°C and stresses from 80 MPa to 240 MPa in vacuum. The creep curves show a rapid transition from primary to steady-state creep with a well-defined activation energy. Microstructural observations show that the creep deformation occurs mainly in the B2 matrix and is controlled by dislocation mechanisms. Samples which had been coldrolled and annealed to reduce the size of A 15 precipitates and increase the yield strength were found to have lower creep resistance than those with unrefined microstructures. The significance of these observations for the creep mechanisms is discussed.

The Investigation of Creep Behavior for NiAl-28Cr-5.5Mo-0.5Hf-0.02wt.%P Alloy at High Temperature

2011 ◽  
Vol 279 ◽  
pp. 28-32
Author(s):  
Guang Ye Zhang ◽  
Dong Wen Ye ◽  
Jin Lin Wang ◽  
You Ming Chen ◽  
Long Fei Liu ◽  
...  
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Creep Behavior ◽  
Fracture Behavior ◽  
Primary Creep ◽  
Dislocation Climb ◽  
Steady State Creep ◽  
Creep Fracture ◽  
Creep Mechanisms ◽  
Higher Temperature

The Microstructure and creep behavior for NiAl-28Cr-5.5Mo-0.5Hf-0.02wt.%P alloy at high temperature have been investigated in this paper. The results reveal that the high temperature creep behavior of the NiAl-28Cr-5.5Mo-0.5Hf-0.02wt.%P alloy is characterized by transient primary creep and dominant steady-state creep as well as ternary creep behavior. The primary creep can be described by Garofalo equation and the steady-state creep can be depicted by Dorn equation. The creep mechanisms are viscous glide of dislocations at lower and middle testing temperatures and dislocation climb at higher temperature. No change of the microstructure for the testing alloy indicates that the creep fracture is controlled by the formation and propagation of cavities and cracks, and the creep fracture behavior obeys Monk man-Grant relationship.

High Temperature Creep Behavior of Zn-1.0Cu-0.2Ti Alloy

2011 ◽  
Vol 287-290 ◽  
pp. 769-776 ◽  
Author(s):  
Lai Rong Xiao ◽  
Xi Min Zhang ◽  
Yan Wang ◽  
Wei Li ◽  
Quan Sheng Sun ◽  
...  
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Creep Rate ◽  
Grain Boundary ◽  
Testing Machine ◽  
Steady State Creep ◽  
Diffusional Creep ◽  
High Temperature Creep ◽  
Steady State Creep Rate ◽  
Temperature Creep

In the present work, Zn-1.0Cu-0.2Ti alloy was prepared by melt casting and extruding processes. High temperature creep property of the alloy was determined using electronic creep relaxation testing machine. Microstructures of the alloy before and after creep test were observed and its high temperature creep mechanism was discussed. The results show that the steady-state creep rate of the alloy increases with temperature and stress. The logarithm of steady-state creep rate (ln) shows a linearity relationship with the logarithm of the stress (lnσ) and reciprocal of temperature (1/T). The stress exponent and apparent activation energy for creep have been determined to be 5.10 and 83.7 kJ/mol, separately. The predominant mechanism is mainly self-diffusional creep. The second phases on the grain boundary can block the slip of grain boundary and dislocation motion which can improve creep resistance of the alloy.

High Temperature Strength and Stability of Oxide Dispersion Hardened Alloys

1975 ◽  
Vol 33 ◽  
pp. 174-175
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
Activation Energy ◽  
Steady State ◽  
High Temperature ◽  
High Stability ◽  
High Strength ◽  
Steady State Creep ◽  
High Temperature Strength ◽  
Oxide Dispersion ◽  
Steady State Creep Rate ◽  
Image Position

The creep behavior of oxide dispersed alloys can be described by the following equation:where ε is steady state creep rate, σ applied stress, R gas constant, T temperature in °K, Qc activation energy for creep, n stress exponent, A and n are constants.Two unusual observations in the case of O.D. alloys are that Qc and n take on values that have not been explained satisfactorily. This investigation was undertaken to explain the unusually high strength, high Qc and high stability (high value of n) in the oxide dispersed alloys.

scholarly journals High Temperature Steady-State Creep Deformation of Cu-Al Solid Solutions

1973 ◽  
Vol 37 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Shiomi Kikuchi ◽  
Mikio Kajitani ◽  
Toshio Enjyo ◽  
Masao Adachi
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Solid Solutions ◽  
Creep Deformation ◽  
Steady State Creep

Microstructure and Creep Property of DZ125 Nickel-Based Superalloy

2013 ◽  
Vol 747-748 ◽  
pp. 697-702 ◽  
Author(s):  
Su Gui Tian ◽  
Xian Lin Meng ◽  
Ning Tian ◽  
Hui Chen Yu
Keyword(s):  
Activation Energy ◽  
Steady State ◽  
High Temperature ◽  
Deformation Mechanism ◽  
Creep Property ◽  
Steady State Creep ◽  
Nickel Based Superalloy ◽  
Microstructure Observation ◽  
Initiation And Propagation ◽  
Property Measurement

By means of creep property measurement and microstructure observation, an investigation has been made into the creep behaviors of DZ125 superalloy at high temperature and low stress. Results showed that the superalloy under the applied stress of 137MPa at 1293 K displayed a better creep resistance, and the apparent creep activation energy of the alloy during steady state creep was measured to be Q = 325.57 kJ/mol. The various microstructures were displayed in different regions of the sample, thereinto, the rafted γ phase was uniformly distributed in the regions far away from the fracture, but the twisted and coarser rafted γ phase appeared in the region near the fracture. The deformation mechanism of the alloy during steady state creep was the dislocations climbing over the rafted γ phase. In the later stage of creep, significant amount of dislocations shearing into the rafted γ-phase promoted the initiation and propagation of the cracks along the boundaries up to the occurrence of fracture, which was though to the fracture mechanism of the alloy during creep.

Study on Thermal Cycling of Sn0.7Cu Solder

2013 ◽  
Vol 791-793 ◽  
pp. 362-365
Author(s):  
Li Yang ◽  
Ju Li Li ◽  
Jing Guo Ge ◽  
Meng Li ◽  
Nan Ji
Keyword(s):  
Shear Stress ◽  
Steady State ◽  
High Temperature ◽  
Thermal Cycling ◽  
Shear Strain ◽  
Maximum Shear Stress ◽  
Steady State Creep ◽  
Maximum Shear Strain ◽  
Cycle Number ◽  
State Cycle

Thermal cycling of a unit Sn0.7Cu solder was studied based on the steady-state creep constitutive equation and Matlab software. The results show that there is a steady-state cycle for the thermal cycling of unit Sn0.7Cu eutectic solder. In steady-state thermal cycling, the shear stress is increased with the increase of temperature. There is a stage of stress relaxation during high temperature. A liner relationship between maximum shear stress and maximum shear strain is observed during thermal cycling. The metastable cycle number is declined greatly with the increase of maximum shear strain.

Sign in / Sign up

Export Citation Format

Share Document