The effect of silica-containing binders on the titanium/face coat reaction

Technical Report · Fri Nov 01 04:00:00 UTC 1996

DOI:https://doi.org/10.2172/414395· OSTI ID:414395

Frueh, C; Poirier, D R ^[1]; Maguire, M C ^[2]

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1. Univ. of Arizona, Tucson, AZ (United States). Dept. of Materials Science and Engineering
2. Sandia National Labs., Albuquerque, NM (United States). Liquid Metal Processing Lab.

The interactions of CP-Ti and Ti-6Al-4V with investment molds containing alumina/silica and yttria/silica face coat systems were studied. Containerless melting in a vacuum was employed and small test samples were made by drop casting into the molds. The effects of the face coat material and mold preheat temperatures on the thickness of the alpha case on the castings were evaluated with microhardness and microprobe measurements. It was found that the thickness of the alpha case was the same, whether a yttria/silica or alumina/silica face coat was used, indicating that the silica binder reacted with the titanium. Hence, the use of expensive refractories, such as yttria, represents an unnecessary cost when combined with a silica binder. It was also found that the alloyed titanium castings had a thinner alpha case than those produced from CP-Ti, which suggests that the thickness of the alpha case depends on the crystal structure of the alloy during cooling from high temperatures. Furthermore, castings made in small yttria crucibles used as molds exhibited little or no alpha case.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 414395
• Report Number(s): SAND--96-2712; ON: DE97001471
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
ALUMINIUM OXIDES
CASTING
CASTING MOLDS
CASTINGS
CRUCIBLES
EXPERIMENTAL DATA
MATERIALS
TEMPERATURE DEPENDENCE
TITANIUM
TITANIUM BASE ALLOYS
VANADIUM ALLOYS
YTTRIUM OXIDES