Abstract
The crystallization kinetics during the liquid to solid phase transformation of pure aluminium and various Al-Ti-B alloys is investigated using differential thermal analysis (DTA) and three-dimensional X-ray diffraction (3D XRD). A reduced undercooling required to activate nucleation of aluminum grains is observed, when both solute titanium and TiB2 particles are present in the liquid. The cooling rate dependence of the onset temperature To, the crystallization peak temperature TP, and the latent heat ΔH are evaluated and compared for all samples. The DTA curves for slow cooling of an Al-0.3Ti-0.02B (wt.%) alloy illustrate the formation of an aluminide phase (TiAl3) upon solidification. A comparison of the DTA curves during slow cooling of the hypoperitectic Al-0.1Ti-0.1TiB2 (wt.%) and the hyperperitectic Al-0.3Ti-0.02B (wt.%) alloys seem to exhibit a kinetic similarity at the onset of the solidification. In situ 3D XRD measurements clearly exhibit the formation of a metastable TiAl3 phase prior to solidification of both alloys. This explains the mechanism of grain refinement in the presence of solute titanium and TiB2 particles in the grain refined aluminum alloys. The influence of titanium diffusion, latent heat, and cooling rate on the growth behaviour of individual aluminium grains during the phase transformation is further quantified.
| Original language | English |
|---|---|
| Pages (from-to) | 18-32 |
| Number of pages | 15 |
| Journal | Materials Science and Engineering A |
| Volume | 416 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 25 Jan 2006 |
| Externally published | Yes |
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Keywords
- Aluminum alloy
- DTA
- Kinetics
- Nucleation
- Synchrotron
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
Cite this
In situ investigation of the crystallization kinetics and the mechanism of grain refinement in aluminum alloys. / Iqbal, N.; van Dijk, N. H.; Offerman, S. E.; Geerlofs, N.; Moret, M. P.; Katgerman, L.; Kearley, G. J.
In: Materials Science and Engineering A, Vol. 416, No. 1-2, 25.01.2006, p. 18-32.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - In situ investigation of the crystallization kinetics and the mechanism of grain refinement in aluminum alloys
AU - Iqbal, N.
AU - van Dijk, N. H.
AU - Offerman, S. E.
AU - Geerlofs, N.
AU - Moret, M. P.
AU - Katgerman, L.
AU - Kearley, G. J.
PY - 2006/1/25
Y1 - 2006/1/25
N2 - The crystallization kinetics during the liquid to solid phase transformation of pure aluminium and various Al-Ti-B alloys is investigated using differential thermal analysis (DTA) and three-dimensional X-ray diffraction (3D XRD). A reduced undercooling required to activate nucleation of aluminum grains is observed, when both solute titanium and TiB2 particles are present in the liquid. The cooling rate dependence of the onset temperature To, the crystallization peak temperature TP, and the latent heat ΔH are evaluated and compared for all samples. The DTA curves for slow cooling of an Al-0.3Ti-0.02B (wt.%) alloy illustrate the formation of an aluminide phase (TiAl3) upon solidification. A comparison of the DTA curves during slow cooling of the hypoperitectic Al-0.1Ti-0.1TiB2 (wt.%) and the hyperperitectic Al-0.3Ti-0.02B (wt.%) alloys seem to exhibit a kinetic similarity at the onset of the solidification. In situ 3D XRD measurements clearly exhibit the formation of a metastable TiAl3 phase prior to solidification of both alloys. This explains the mechanism of grain refinement in the presence of solute titanium and TiB2 particles in the grain refined aluminum alloys. The influence of titanium diffusion, latent heat, and cooling rate on the growth behaviour of individual aluminium grains during the phase transformation is further quantified.
AB - The crystallization kinetics during the liquid to solid phase transformation of pure aluminium and various Al-Ti-B alloys is investigated using differential thermal analysis (DTA) and three-dimensional X-ray diffraction (3D XRD). A reduced undercooling required to activate nucleation of aluminum grains is observed, when both solute titanium and TiB2 particles are present in the liquid. The cooling rate dependence of the onset temperature To, the crystallization peak temperature TP, and the latent heat ΔH are evaluated and compared for all samples. The DTA curves for slow cooling of an Al-0.3Ti-0.02B (wt.%) alloy illustrate the formation of an aluminide phase (TiAl3) upon solidification. A comparison of the DTA curves during slow cooling of the hypoperitectic Al-0.1Ti-0.1TiB2 (wt.%) and the hyperperitectic Al-0.3Ti-0.02B (wt.%) alloys seem to exhibit a kinetic similarity at the onset of the solidification. In situ 3D XRD measurements clearly exhibit the formation of a metastable TiAl3 phase prior to solidification of both alloys. This explains the mechanism of grain refinement in the presence of solute titanium and TiB2 particles in the grain refined aluminum alloys. The influence of titanium diffusion, latent heat, and cooling rate on the growth behaviour of individual aluminium grains during the phase transformation is further quantified.
KW - Aluminum alloy
KW - DTA
KW - Kinetics
KW - Nucleation
KW - Synchrotron
UR - http://www.scopus.com/inward/record.url?scp=30844440523&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2005.10.045
DO - 10.1016/j.msea.2005.10.045
M3 - Article
VL - 416
SP - 18
EP - 32
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
IS - 1-2
ER -