Oxidation processes and phase changes in metastable Al-Ti mechanical alloys

Document Type

Conference Proceeding

Publication Date

1-1-2003

Abstract

Oxidation of Al-Ti mechanical alloys with Ti concentrations from 5 to 25 at% was studied and compared to the oxidation of Al powders using thermal analysis in the temperature range of 300 - 1500 °C in oxygen. Differential scanning calorimetry (DSC) and differential thermal analysis (DTA) with simultaneous thermo-gravimetric analysis (TGA) were used to monitor phase changes and oxidation reactions. Intermediate reaction products were recovered at different temperatures and analyzed using x-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxidation of all samples occurred stepwise. The temperature of the first oxidation step for Al-Ti mechanical alloys correlates with the exothermic formation of the Al-Ti intermetallic at T>700 °C and has a higher rate and greater degree of oxidation than the first oxidation step observed for pure aluminum. The second and third oxidation steps in mechanical alloys and aluminum occur at higher temperatures and both appear to be controlled by changes in the permeability of the Al2O 3 films. The effect of the Al2O3 film becomes less noticeable at increased Ti concentrations.

Identifier

2442449200 (Scopus)

Publication Title

Materials Research Society Symposium Proceedings

External Full Text Location

https://doi.org/10.1557/proc-800-aa3.4

ISSN

02729172

First Page

99

Last Page

104

Volume

800

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