IMPROVEMENT OF HIGH-STRENGTH ALUMINUM CASTINGS. Final Report for August 27, 1958-August 27, 1959

Technical Report · Wed Jun 01 00:00:00 EDT 1960

OSTI ID:4078202

Lillie, C R; Simcoe, C R

Commercially available high-strength aluminum-base casting alloys containing approximately 10% magnesium suffer from a serious decrease in tensile ductility after being stored at room temperature for about a year. This program was aimed at determining the metallurgical processes which accompany such aging behavior, and at investigating compositional modifications which would aid in maintaining ductility by altering the product of aging and/ or the kinetics of the reaction. Comparison of the aging behavior of a commercial Al- 10 Mg alloy (No. 220 alloy) and a high-purity Al- 10 Mg alloy showed that the aging behavior of such alloys is relatively insensitive to variation in either solution treatment or cooling rate after solution treatment. The commercial 220 alloy overaged in 1000 hr only at an aging temperature of 180 deg C, while the high- purity alloy overaged in the same time period at aging temperatures of 80 deg C and above. There is evidence that the commercial 220 alloy may be stabilized against change in hardness due to room-temperature aging for times up to 1000 hr by preliminary aging at 60, 100, or 150 deg C. A second phase of this program concerned an investigation of compositional modifications of an experimental alnminum-base casting alloy, X-250. The X-250 alloy, containing 8% Mg, 1.5% Zn, 0.25% Mn, and 0.l5% Cu, is reputedly nearly non-aging at room temperature. Evidence obtained from hardness-time curves for aging at 150 deg C indicates that the X-250 alloy ages more rapidly and to a greater extent than do alloys of the following novel compositions: Al-8 Mg-1 Mn-0.1 Ti-0.003 Be, Al-8 Mg-1 Cu-0.1 Ti- 0.003 Be, and Al-8 Mg-2 Cr-0.1 Ti-0.003 Be. (auth)

• Research Organization: Illinois Inst. of Tech., Chicago. Armour Research Foundation
• DOE Contract Number: DA-11-022-507-ORD-2890
• NSA Number: NSA-15-011570
• OSTI ID: 4078202
• Report Number(s): ARF-2157-12; AD-240237
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-61
• Country of Publication: United States
• Language: English

Related Subjects

METALS, CERAMICS, AND OTHER MATERIALS
ADDITIVES
ALUMINUM
ALUMINUM ALLOYS
BERYLLIUM
BERYLLIUM ALLOYS
CASTING
CHEMICALS
CHROMIUM ALLOYS
COOLING
COPPER
COPPER ALLOYS
DIAGRAMS
DUCTILITY
EFFICIENCY
ELEMENTS
HARDNESS
HEAT TREATMENTS
IMPURITIES
MAGNESIUM ALLOYS
MANGANESE
MANGANESE ALLOYS
METALLURGY
REACTION KINETICS
STABILITY
STANDARDS
STORAGE
TEMPERATURE
TENSILE PROPERTIES
TITANIUM
TITANIUM ALLOYS
VARIATIONS
ZINC ALLOYS