Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Temperature-dependent stability of θ'-Al2Cu precipitates investigated with phase field simulations and experiments

Journal Article · · Materialia
 [1];  [2];  [3];  [3];  [3];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); The Univ. of Tennessee, Knoxville, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
+ Show Author Affiliations

The upper limit of service temperature for many Al-Cu alloys is determined by the thermal stability of strengthening θ' (Al2Cu) precipitates. Above a certain temperature, θ' precipitates will undergo morphological evolution and transform into the detrimental, equilibrium θ phase, leading to a rapid drop in strength. Certain alloying elements have recently been reported to increase the thermal stability of θ' precipitates, by mechanisms that are yet unclear. Herein, we investigate the effect of modified interfacial energy and solute chemical mobility on the thermal stability of θ' via high-throughput phase field study. We identify a critical θ' aspect ratio to predict the onset of θ formation. Using this criterion, we predict the time required for θ' to θ phase transformation as a function of temperature, Cu diffusivity, and the interfacial energy of θ' precipitates. The predicted times compare favorably with reported times for θ formation under similar experimental conditions. Furthermore, these phase field simulations predict that a moderate reduction in Cu mobilityis adequate to stabilize the as-aged microstructure up to 300 °C, while substantial reductions to both interfacial energy and Cu mobility are needed to achieve similar stability at 400 °C. Experimental microstructural evolution results in commercial (319) and thermally stabilized (RR350) cast aluminum alloys are presented to complement the simulations.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
DOE Office of Science; USDOE
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1502601
Alternate ID(s):
OSTI ID: 1547918
Journal Information:
Materialia, Journal Name: Materialia Journal Issue: C Vol. 5; ISSN 2589-1529
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

Similar Records

The effects of microstructural stability on the compressive response of two cast aluminum alloys up to 300 °C
Journal Article · Thu Jun 08 00:00:00 EDT 2017 · Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing · OSTI ID:1366385
Mechanisms for stabilizing θ'(Al2Cu) precipitates at elevated temperatures investigated with phase field modeling
Journal Article · Fri Apr 26 00:00:00 EDT 2019 · Materialia · OSTI ID:1558547
Structural deformation and transformation of θ'-Al2Cu precipitate in Al matrix via interfacial diffusion
Journal Article · Wed Sep 25 00:00:00 EDT 2019 · Computational Materials Science · OSTI ID:1784208

Related Subjects

36 MATERIALS SCIENCE
Al-Cu alloys
Coarsening
Kinetics
Phase field simulation
θ′-Al2Cu