INTERNAL FRICTION STUDIES OF HEAVY INTERSTITIAL IMPURITY ATOMS

1985 ◽  
Vol 46 (C10) ◽  
pp. C10-55-C10-58
Author(s):  
C. BÖRNER ◽  
K.-H. ROBROCK
Keyword(s):  
Internal Friction ◽  
Interstitial Impurity ◽  
Impurity Atoms

Internal Friction in Plastically Deformed High-Purity NiAl Single Crystals

1998 ◽  
Vol 552 ◽  
Author(s):  
M. Hirscher ◽  
D. Schaible
Keyword(s):  
Internal Friction ◽  
Single Crystals ◽  
High Purity ◽  
Formation Enthalpy ◽  
Dislocation Motion ◽  
Zone Melting ◽  
Interstitial Impurity ◽  
Impurity Atoms ◽  
Kink Pair ◽  
Friction Measurements

ABSTRACTHigh-purity stoichiometric NiAl single crystals have been prepared by crucible-free inductive zone melting and afterwards well annealed at temperatures below 1200 K. Internal friction measurements of torsionally deformed single crystals show two relaxation maxima at 500 and 800 K which anneal during the measurement. The first maximum can be assigned to the dislocation motion by kinkpair formation and the annealing to pinning of these dislocations by interstitial impurity atoms. The second maximum is attributed to the Snoek-Köster relaxation of dislocations in the presence of mobile interstitial impurity atoms and the annealing to the pinning of dislocations by vacancies. The kink-pair formation enthalpy in NiAl was estimated.

Diffusion mechanism in cutting Ni-based alloy containing γ′ phase (Ni3Al) with CBN tool based on MD simulation

2021 ◽  
pp. 095440542110024
Author(s):  
YiHang Fan ◽  
WenYuan Wang ◽  
ZhaoPeng Hao
Keyword(s):  
Impurity Atom ◽  
Md Simulation ◽  
Diffusion Mechanism ◽  
Interstitial Impurity ◽  
Diffusion Activation Energy ◽  
Temperature Oxidation ◽  
Substitutional Impurity ◽  
Impurity Atoms ◽  
Cbn Tool ◽  
Cutting Model

Ni-based alloys are widely used in aerospace because of their high strength and high temperature oxidation resistance. CBN tool is suitable for precision machining of Ni-based alloy. Diffusion wear is an important wear form of CBN tool in the process of cutting Ni-based alloy. Therefore, it is of great significance to study the diffusion phenomenon in the process of cutting Ni-based alloy with CBN tool. In this paper, the cutting model of Ni-based alloy containing γ′ phase (Ni3Al) with CBN tool is established based on the molecular dynamics (MD) simulation method. The self diffusion activation energy of all kinds of atoms in the workpiece and the formation energy of several point defects in the tool are calculated, so as to study in depth the atom diffusion mechanism according to the simulation results. The results show that the atoms in the crystal boundary of the workpiece are the most easily diffused, followed by the atoms in the phase boundary, and the atoms in the lattice are the most difficult to diffuse. When the workpiece atoms diffuse into the tool, it is easier to diffuse into the tool grain boundary than to form interstitial impurity atoms or displacement impurity atoms. It is more difficult to form the substitutional impurity atom than to form the interstitial impurity atom.

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