Synthesis of metastable aluminum-based intermetallics by mechanical alloying

Conference · Tue Jan 01 00:00:00 EST 1991

DOI:https://doi.org/10.4028/www.scientific.net/MSF.88-90.595· OSTI ID:5750686

Schwarz, R B; Srinivasan, S; Desch, P B

We have used mechanical alloying (MA) to prepare fine-grained powders of Al 25 at. % X (X = Ti, Zr, Hf) having the metastable cubic L1{sub 2} structure. Hexane (C{sub 6}H{sub 14}) is added to the milling media to avoid the agglomeration of the aluminum powder. Carbon from the decomposition of the hexane incorporates into the powder to form a fine dispersion of carbides. These carbides are beneficial because they limit grain growth during consolidation and add strength to the alloy. We have consolidated the mechanically alloyed powders using conventional hot-pressing and non-conventional dynamic pressing. We used hot pressing to consolidate mechanically alloyed L1{sub 2}-Al{sub 3}Ti powder in the presence of excess of Al. The compact has the DO{sub 22} structure. Its room-temperature compressive strength is 1.2 GPa (exceeding that of cast Al{sub 3}Ti by a factor of 10). At 400{degrees}C, the compressive strength decreases to 1 GPa. The ductility, which is negligible at room temperature, increases to 6% at 400{degrees}C. We used dynamic pressing to consolidate L1{sub 2}-Al{sub 5}CuZr{sub 2} powder. The compact, having the L1{sub 2} structure, has fine grains (44 nm) and a fine dispersion of ZrC precipitates (7 nm). Its hardness is in the range of 1030 kg mm{sup {minus}2}. Current efforts are to investigate ternary alloys based on fine-grained trialuminides which include a ductile second phase. 26 refs., 8 figs.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5750686
• Report Number(s): LA-UR-91-1490; CONF-9105182-2; ON: DE91013651
• Resource Relation: Journal Volume: 88-90; Conference: International symposium on mechanical alloying, Kyoto (Japan), 7-10 May 1991
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
SYNTHESIS
TITANIUM ALLOYS
ZIRCONIUM ALLOYS
CARBIDES
HAFNIUM ALLOYS
HEXANE
HOT PRESSING
INTERMETALLIC COMPOUNDS
POWDERS
TRANSMISSION ELECTRON MICROSCOPY
ALKANES
ALLOYS
ALUMINIUM ALLOYS
CARBON COMPOUNDS
ELECTRON MICROSCOPY
FABRICATION
HYDROCARBONS
MATERIALS WORKING
MICROSCOPY
ORGANIC COMPOUNDS
PRESSING
360101* - Metals & Alloys- Preparation & Fabrication