The role of boron in the grain refinement of aluminum with titanium

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Metall. Trans., A; (United States)

DOI:https://doi.org/10.1007/BF02649476· OSTI ID:6977540

Guzowski, M M; Sigworth, G K; Sentner, D A

It has been known for nearly forty years that the presence of boron in Al-Ti grain refiners has a beneficial effect. Three major theories have been proposed to explain the phenomenon: 1. Boron alters important phase relationships in the Al-Ti-B system. 2. Boron forms TiB/sub 2/, which is nearly insoluble and acts as an effective nucleus for grain refining. 3. A metastable phase, (Al,Ti)B/sub 2/, forms and either acts directly as a grain refining agent, or somehow alters the phase relationships as in (1) above. A close examination of these theories, however, shows that none is wholly satisfactory in explaining the experimental evidence. Hence, experimental work was carried out to elucidate further the important role of boron. The (Al, Ti)B/sub 2/ phase was found to be an effective nucleant in some alloys, in agreement with prior work. In addition, this study suggests that boron may at times improve the grain refining response of Al-Ti alloys by altering the surface structure of TiAl/sub 3/ nuclei. The mechanisms of grain refinement, therefore, appear to be more complex than has generally been realized.

• Research Organization: Cabot R and D Labs., Reading, PA (US)
• OSTI ID: 6977540
• Journal Information: Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 18A:4; ISSN MTTAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
BORON ALLOYS
ENERGY LEVELS
EXCITED STATES
GRAIN REFINEMENT
METASTABLE STATES
NUCLEATION
PHASE STUDIES
STRUCTURAL CHEMICAL ANALYSIS
TITANIUM ALLOYS