Effect of the addition of Ag on the strengthening of Al{sub 3}Li phase in Al-Li single crystals

Journal Article · Fri Jul 24 04:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00117-7· OSTI ID:634663

Lee, B C; Park, J K ^[1]

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1. Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Materials Science and Engineering

The variation of the critical resolved shear stress as a function of aging condition has been measured in ternary Al-{approximately}(1.9--2.0) wt % Li- {approximately}0.4 wt % Ag single crystals and has been analyzed using the same version of order-hardening theory as in the previous work in binary single crystals. The result showed that the antiphase boundary energy of the Al{sub 3}Li lattice on {l_brace}111{r_brace} definitively increases from about 0.118 J/m{sup 2} in binary crystals to 0.128 {+-} 0.012 J/m{sup 2} in ternary crystals, in good agreement with the analysis of the transition behavior from shearing to looping and of the dislocation pair spacings. A strong segregation tendency of Ag into the Al{sub 3}Li lattice is believed to be responsible for this increment. The previous result of {gamma}{sub apb} (0.118 {+-} 0.006 J/m{sup 2}) in binary crystals is, although unlikely from the recent suggestion of Nembach, the best value one can obtain from the recent knowledge of order-hardening theory. This is slightly larger than that (about 0.100 J/m{sup 2}) obtained from the analysis of the transition from shearing to looping and somewhat larger than the result (about 0.085 J/m{sup 2}) of the first-principles calculation. Three factors are discussed as principal causes of a possibility of an overestimation of {gamma}{sub apb} on applying order-hardening theory.

• OSTI ID: 634663
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 12 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
ALUMINIUM ALLOYS
INTERMETALLIC COMPOUNDS
LITHIUM ALLOYS
METALLURGICAL EFFECTS
MONOCRYSTALS
SHEAR PROPERTIES
SILVER ADDITIONS