BERYLLIUM CASTING, PHASE II. Final Report, September 19, 1958-December 15, 1960

Technical Report · Tue Oct 31 00:00:00 EST 1961

OSTI ID:4059384

Taber, K C; Harris, R C

A reliable technique for producing fine-grained, sound beryllium cast ingots was developed. Four approaches to obtain grain refinement were evaluated including; alloying additions, inoculation, mold vibration, and accelerated cooling through mold design. Of these, the latter was the most effective in achieving sound, fine-grained ingots. The alloying additions in varying amounts of lanthanum, zirconium, germanium, and silver were evaluated for grain refinement effects. Five ingots were poured with lanthanum additions of 0.07% to O.5%. lngot XP-183 with 0.07% lanthanum produced the lowest average grain size of 0.115 (mm) in this series. Thirteen ingots containing zirconium additions from 0.15% to 2.43% were evaluated. Ingot XP-186 in this group with 0.27% zirconium had a low average grain size of 0.097 (mm). Eleven germanium alloy castings were poured with germanium concentrations of less than 15 ppm to 0.69%. ln this series ingot XP-96, having 0.13% germanium, had the lowest average grain size of 0.101 (mm). The silver alloy series included six castings. The amount of silver additions varied from 0.23% to 16.1% with ingot XP0.137 (mm). The zirconium alloy containing 0.27% zirconium, poured at 1350 deg C into a cold 1.5-in. diameter mold produced the lowest average grain size. Other alloying elements including aluminum, titanium, silicon, and silver were used either singly or in combination to evaluate their effect on surface finish, apparent fluidity of the melt, and ingot soundness. Fifteen heats were poured. The silicon and titanium in combination produced good fluidity and sound castings were produced using a combination of titanium, silicon, and silver. Tantalum nitride and tungsten carbide were found to be ineffective as inoculants, in the concentrations obtained in the eighteen melts poured. The use of a low frequency mechanical vibration of the mold produced grain refinement in six ingots poured. The study suggests that a higher energy in either frequency or amplitude would be beneficial in breaking up the columnar grains as they grow during solidification. The use of heavy-walled molds made of high thermal conductivity materials to control solidification rates was most effective in achieving sound, fine-grained ingots. Three fine-grained ingots were extruded at a reduction ratio of 4.5:1. The first ingot containing 0.76% silver was poured at 1300 deg C. The second contained 1.22% silver and was poured under the same conditions. The third ingot was unalloyed beryllium poured at 1400 deg C. No vibration was used on the molds of these ingots. Sections of the first two extrusions were clad and subsequently rolled to 0.090 sheet. Metullographic examination of the sheet indicated that a recrystallized structure can be produced which is equiaxed and has a grain size comparable to hot-pressed beryllium powder. (auth)

• Research Organization: Beryllium Corp., Reading, Penna.
• DOE Contract Number: AF33(600)-37902
• NSA Number: NSA-15-014680
• OSTI ID: 4059384
• Report Number(s): NP-9958
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-61
• Country of Publication: United States
• Language: English

Related Subjects

METALS, CERAMICS, AND OTHER MATERIALS
ALUMINUM ALLOYS
BERYLLIUM
BERYLLIUM ALLOYS
CASTING
CONTROL
CRYSTALLIZATION
EXTRUSION
GERMANIUM ALLOYS
GRAIN SIZE
HEAT TREATMENTS
IMPURITIES
LANTHANUM ALLOYS
MELTING
METALLOGRAPHY
MIXING
QUANTITY RATIO
ROLLING
SHEETS
SILICIDES
SILVER ALLOYS
SOLIDIFICATION
TANTALUM NITRIDES
TITANIUM ALLOYS
TUNGSTEN CARBIDES
VIBRATIONS
ZIRCONIUM ALLOYS