We present first principle calculations on formation and binding energies for Cu and Zn as solute atoms forming small clusters up to nine atoms in Al-Cu and Al-Zn alloys. We employ a density-functional approach implemented using projector-augmented waves and plane wave expansions. We find that some structures, in which Cu atoms are closely packed on (100)-planes, turn out to be extraordinary stable. We compare the results with existing numerical or experimental data when possible. We find that Cu atoms precipitating in the form of two-dimensional platelets on (100)-planes in the fcc aluminum are more stable than three-dimensional structures consisting of the same number of Cu-atoms. The preference turns out to be opposite for Zn in Al. Both observations are in agreement with experimental observations.

Stability of Cu-precipitates in Al-Cu alloys

Folegati, Paola;
2018

Abstract

We present first principle calculations on formation and binding energies for Cu and Zn as solute atoms forming small clusters up to nine atoms in Al-Cu and Al-Zn alloys. We employ a density-functional approach implemented using projector-augmented waves and plane wave expansions. We find that some structures, in which Cu atoms are closely packed on (100)-planes, turn out to be extraordinary stable. We compare the results with existing numerical or experimental data when possible. We find that Cu atoms precipitating in the form of two-dimensional platelets on (100)-planes in the fcc aluminum are more stable than three-dimensional structures consisting of the same number of Cu-atoms. The preference turns out to be opposite for Zn in Al. Both observations are in agreement with experimental observations.
Ab initio calculations; Aluminum copper alloys; DFT-LDA; Guinier-Preston zones; Precipitates; Materials Science (all); Instrumentation; Engineering (all); Process Chemistry and Technology; Computer Science Applications1707 Computer Vision and Pattern Recognition; Fluid Flow and Transfer Processes
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11311/1063342
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