ISSN 2594-5327
51th Congresso anual — Vol. 52 , num. 1 (1997)
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Abstract
Binary Ti alloys containing 14 and 22 at% aluminium with ternary (1 and 3.5 at% silicon), and quaternary (1 at% niobium or zirconium) alloying elements were homogenised at 1300°C and quenched. The effect of alloying elements on the mechanism and morphology of allotropic transformation occurred during quenching, Ti-β(bcc)→Ti-α(hcp), was studied. The different morphologies of α phase observed have been correlated with the possible types of reaction (short and long-range diffusional, and displacive). The morphological observations suggest that the transition between diffusional and shear mechanisms is continuous. The discussion also shows how variables, which can be obtained through thermodynamic modelling of phase diagrams, might be exploited to control the morphology of as-quenched microstructures. Additionally, the effect of the alloying elements on the formation of ordered α2 phase, which also occurred during quenching, was studied and Si addition is shown to promote the formation of α2 domains in quenched alloys.
Binary Ti alloys containing 14 and 22 at% aluminium with ternary (1 and 3.5 at% silicon), and quaternary (1 at% niobium or zirconium) alloying elements were homogenised at 1300°C and quenched. The effect of alloying elements on the mechanism and morphology of allotropic transformation occurred during quenching, Ti-β(bcc)→Ti-α(hcp), was studied. The different morphologies of α phase observed have been correlated with the possible types of reaction (short and long-range diffusional, and displacive). The morphological observations suggest that the transition between diffusional and shear mechanisms is continuous. The discussion also shows how variables, which can be obtained through thermodynamic modelling of phase diagrams, might be exploited to control the morphology of as-quenched microstructures. Additionally, the effect of the alloying elements on the formation of ordered α2 phase, which also occurred during quenching, was studied and Si addition is shown to promote the formation of α2 domains in quenched alloys.
Keywords
Allotropic reaction, Titanium-alloys, Phase Transformations
Allotropic reaction, Titanium-alloys, Phase Transformations
How to cite
Azevedo, C. R. de Farias; Flower, H. M..
Effect of Alloying Elements (Si, Nb and Zr) on the Morphology of the Allotropic Reaction, β(bcc)→α(hcp), in Ti-Al alloys,
p. 1101-1131.
In: 51th Congresso anual,
São Paulo, Brasil,
1997.
ISSN: 2594-5327, DOI 10.5151/2594-5327-C00072-1101-1131
