On the TEM/EDS verification of Tu-Turnbill model of discontinuous dissolution

Journal Article · Sun May 01 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90335-2· OSTI ID:5264594

Zieba, P; Morgiel, J ^[1]

---

1. Polish Academy of Sciences, Cracow (Poland). Inst. for Metals Research

Discontinuous dissolution (DD) occurs by a receding of boundaries of cellular precipitates towards positions of original grain boundaries. The theoretical description of that process with an equation describing the solute transport at receding boundary was derived by Tu and Turnbull. One of conclusions resulting from the Tu-Turnbull model is that DD leads to the formation of an inhomogeneous [alpha][approximately] solid solution. This inhomogeneity is represented by C*, the solute concentration in the [alpha][approximately] solid solution at the position corresponding to the tip of the solute rich lamella. It is expected that the solute content in this place is greater than the equilibrium concentration at the temperature at which the DD takes place. This prediction was qualitatively confirmed by structural investigations, which revealed a peculiar ghost image'' at the previous location of the solute rich lamellae. In the present experiment, measurements of a local composition in AlZn thin foils were performed using the EDS system in a transmission electron microscope. The results were used to calculate the diffusivity at the receding cells boundary, according to the equation proposed by Tu and Turnbull.

• OSTI ID: 5264594
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 30:9; ISSN 0956-716X; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
CHEMICAL COMPOSITION
COHERENT SCATTERING
DIFFRACTION
DIFFUSION
ELECTRON DIFFRACTION
MATHEMATICAL MODELS
MICROSTRUCTURE
PRECIPITATION
SCATTERING
SEPARATION PROCESSES
ZINC ALLOYS