Orientation relationship between {beta}-Mn and L2{sub 1} matrix in a Cu{sub 2}MnAl alloy

Journal Article · Thu Jul 01 04:00:00 EDT 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-0170-1· OSTI ID:677980

Chu, K C; Liu, T F ^[1]

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1. National Chiao Tung Univ. (Taiwan, Province of China). Dept. of Materials Science and Engineering

In the as-quenched condition, the microstructure of the Cu{sub 2}MnAl alloy was L2{sub 1} phase containing extremely fine L-J precipitates. This result is different from that reported by other workers in the as-quenched Cu{sub 2}MnAl alloy. When the as-quenched alloy was aged at 350 C, {gamma}-brass precipitates started to appear within the L2{sub 1} matrix. The orientation relationship between the {gamma}-brass and the L2{sub 1} matrix was determined to be cubic to cubic. This result is consistent with that observed by other workers in the aged Cu-Mn-Al alloy. When the alloy was aged at 460 C, the {gamma}-brass precipitates disappeared and platelike {beta}-Mn precipitates occurred within the L2{sub 1} matrix. As the aging temperature was increased to 560 C, the morphology of the {beta}-Mn precipitates changed from platelike to granular shape. Electron diffraction examinations indicated that in spite of the morphology change the same orientation relationship between the {beta}-Mn and the L2{sub 1} matrix is maintained, and it could be best stated as follows: (210){sub {beta}-Mn}{parallel}(100){sub m}, ({bar 1}20){sub {beta}-Mn}{parallel}(010){sub m}, (001){sub {beta}-Mn}{parallel}(001){sub m}. This result is in disagreement with that reported by Kuzobski et al. in the aged Cu{sub 2}MnAl alloy. In their study, it was concluded that both the morphology of the {beta}-Mn precipitates and the orientation relationship between the {beta}-Mn and the L2{sub 1} matrix would vary with the aging temperature.

• Sponsoring Organization: USDOE
• OSTI ID: 677980
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 7 Vol. 30; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
ALUMINIUM ALLOYS
COPPER ALLOYS
INTERMETALLIC COMPOUNDS
MANGANESE ALLOYS
MICROSTRUCTURE
ORIENTATION
PRECIPITATION
QUENCHING