Characterization of the high-temperature phase fields near stoichiometric γ-TiAl

Autor:	S. C. Huang, Paul Alfred Siemers
Rok vydání:	1989
Předmět:	Phase boundary Materials science Mechanics of Materials Phase (matter) Metallurgy Metals and Alloys Metallography Hexagonal phase Ingot Condensed Matter Physics Microstructure Stoichiometry Phase diagram
Zdroj:	Metallurgical Transactions A. 20:1899-1906
ISSN:	2379-0180 0360-2133
DOI:	10.1007/bf02650276
Popis:	The phase fields above ∼1250°C in the Ti−Al system containing 46 to 55 at. pct Al were characterized using consolidated rapid solidification-processed materials. The characterization techniques used included metallography after heat treatments and dilatometry. Ingot solidification microstructures were also evaluated. The results indicate the existence of a hexogonal phase with transus temperatures ranging from ∼1325°C at 46 at. pct Al to ∼1440°C at the solubility limit of ∼51 at. pct Al. These results agree well with the Margolin Ti−Al phase diagram. Other results relating to the melting and solidification of the hexagonal phase are also consistent. The present measurements, however, show a much wider γ+hexagonal phase field, since the determined γ-TiAl phase boundary runs from the peritectic composition of ∼52.5 at. pct Al at ∼ 1440°C to ∼51 at. pct Al at 1250°C. It is possible that the large two-phase field is partially due to the 600 to 900 ppm oxygen present in the studied materials.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7ae3aa4ad964d27b25120eb54b6c79b2 https://doi.org/10.1007/bf02650276 Zobrazit plný text záznamu