Precipitation of T₁ and θ Phase in Al-4{C}u-1Li-0.25Mn During Age Hardening: Microstructural Investigation and Phase-Field Simulation
I. Haeusler, C. Schwarze, M. U. Bilal, D. V. Ramirez , W. Hetaba, R. D. Kamachali, B. Skrotzki,
Volume: 10.
DOI: 10.3390/ma10020117
Published: 2017
Abstract
Experimental and phase field studies of age hardening response of
a high purity Al-4Cu-1Li-0.25Mn-alloy (mass %) during isothermal
aging are conducted. In the experiments, two hardening phases are
identified: the tetragonal ?? (Al2Cu) phase and the hexagonal T1
(Al2CuLi) phase. Both are plate shaped and of nm size. They are analyzed
with respect to the development of their size, number density and
volume fraction during aging by applying different analysis techniques
in TEM in combination with quantitative microstructural analysis.
3D phase-field simulations of formation and growth of ?? phase are
performed in which the full interfacial, chemical and elastic energy
contributions are taken into account. 2D simulations of T1 phase
are also investigated using multi-component diffusion without elasticity.
This is a first step toward a complex phase-field study of T1 phase
in the ternary alloy. The comparison between experimental and simulated
data shows similar trends. The still unsaturated volume fraction
indicates that the precipitates are in the growth stage and that
the coarsening/ripening stage has not yet been reached.