Relation between the activation energies of high-temperature creep and diffusion in transition metal carbides

1971 ◽  
Vol 3 (9) ◽  
pp. 1058-1061 ◽  
Author(s):  
P. V. Zubarev ◽  
L. N. Dement'ev
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Activation Energies ◽  
High Temperature Creep ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Temperature Creep ◽  
And Diffusion

scholarly journals Molecular Dynamics Simulation of High-Temperature Creep Behavior of Nickel Polycrystalline Nanopillars

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2606
Author(s):  
Xiang Xu ◽  
Peter Binkele ◽  
Wolfgang Verestek ◽  
Siegfried Schmauder
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Grain Boundary ◽  
Creep Behavior ◽  
Activation Energies ◽  
Dynamics Simulation ◽  
Dislocation Creep ◽  
Creep Process ◽  
High Temperature Creep ◽  
Temperature Creep

As Nickel (Ni) is the base of important Ni-based superalloys for high-temperature applications, it is important to determine the creep behavior of its nano-polycrystals. The nano-tensile properties and creep behavior of nickel polycrystalline nanopillars are investigated employing molecular dynamics simulations under different temperatures, stresses, and grain sizes. The mechanisms behind the creep behavior are analyzed in detail by calculating the stress exponents, grain boundary exponents, and activation energies. The novel results in this work are summarized in a deformation mechanism map and are in good agreement with Ashby’s experimental results for pure Ni. Through the deformation diagram, dislocation creep dominates the creep process when applying a high stress, while grain boundary sliding prevails at lower stress levels. These two mechanisms could also be coupled together for a low-stress but a high-temperature creep simulation. In this work, the dislocation creep is clearly observed and discussed in detail. Through analyzing the activation energies, vacancy diffusion begins to play an important role in enhancing the grain boundary creep in the creep process when the temperature is above 1000 K.

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