The critical resolved shear stress of peak-aged aluminium–lithium single crystals

Kalogeridis, Avraam; Pešička, Josef; Nembach, E.

doi:10.1016/s1359-6454(99)00018-x

Cited by 7 publications

(3 citation statements)

References 34 publications

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“…Using equation (1 b) with R iˆb instead of equation (3 b) yields ® APBˆ0 :146 J m 2 . These results are much higher than the value ® APBˆ0 :117 0:014 J m 2 derived by Kalogeridis et al (1999) and Nembach (2000) from measurements of the CRSS of peak-aged Al±Li single crystals. As stated above, the most likely reason for this discrepancy are errors due to cross-slipped segments of the loops.…”

Section: Al±licontrasting

confidence: 54%

“…Samples of this alloy were compression tested at 283 K up to 4% technical strain. The total CRSS ½ t was 10.3 MPa (Kalogeridis et al 1999).…”

Section: …2 †mentioning

confidence: 99%

“…Using these values and R iˆb , equation (3 b) yields ½ self;critˆ7 42 MPa. With the CRSS ½ tˆ1 0:3 MPa (Kalogeridis et al 1999), equation (3 a) yields a speci®c APB energy ® APBˆ0 :215 J m 2 . With a larger inner cut-o radius R iˆ2 b, ® APB is smaller by about 13%.…”

Section: Al±limentioning

confidence: 99%

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Derivation of the antiphase-boundary energy of L1 2 long-range-ordered precipitates from measurements of the minimum size of stable dislocation loops

Baither¹,

Mohles²,

Nembach³

2001

Philosophical Magazine Letters

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In an alloy that is strengthened by long-range-ordered particles, a matrix dislocation generates an antiphase boundary (APB) when it cuts through such a particle. The speci®c energy ® APB of this APB has been measured for two fcc alloys with spherical coherent L1 2 ordered particles: an Al±7.5 at.% Li-alloy and the commercial Ni-base superalloy Nimonic PE16. Peak-aged specimens have been deformed and Orowan loops searched for using transmission electron microscopy. ® APB has been derived from the radii of the smallest dislocation loops which have been left behind around particles. Such an approach had been used previously, for example, by Raynor and Silcock and by Nembach et al. Here an improved evaluation method has been applied; it is based on the results of computer simulations of the equilibrium con®gurations of dislocation loops.} 1. Introduction A dislocation in a disordered matrix cutting through a coherent L1 2 long-rangeordered precipitate generates an antiphase boundary (APB) inside this particle. This causes a stress which tends to drive the dislocation back out of the particle. Hence dislocation glide is impeded and the material is strengthened. Such a hardening mechanism is e ective for instance in Al-rich Al±Li alloys and in the commercial nickel-base superalloy Nimonic PE16 (Nembach and Neite 1985, Nembach 1996, 2000.The strengthening contribution of these L1 2 long-range ordered precipitates strongly depends on the energy density ® APB of the APB. To measure this important strengthening parameter ® APB , several approaches have been used in the past. For spherical particles, one method is to measure the minimum radius r min of Orowan loops found around the L1 2 -ordered precipitates in a specimen that has been deformed up to the external resolved stress ½ ext (Raynor andSilcock 1970, Nembach et al. 1992). To derive ® APB from r min , a model for the interaction of the Orowan loop with itself is required. Nembach et al. (1992) based their derivation of the function ® APB (r min ) on the mean self-stress ½ self;mean of a circular loop as calculated by Brown (1964):

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Section: Al±licontrasting

confidence: 54%

“…Samples of this alloy were compression tested at 283 K up to 4% technical strain. The total CRSS ½ t was 10.3 MPa (Kalogeridis et al 1999).…”

Section: …2 †mentioning

confidence: 99%

See 1 more Smart Citation

Derivation of the antiphase-boundary energy of L1 2 long-range-ordered precipitates from measurements of the minimum size of stable dislocation loops

Baither¹,

Mohles²,

Nembach³

2001

Philosophical Magazine Letters

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Bibliography

2014

Aluminum-Lithium Alloys

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Evaluation of corrosion behaviour of AlÀMgÀLi alloys in sea water. J. Mater. Eng. Perform. 5, 235À240. Ahmadi, S., Arabi, H., Shokuhfar, A., 2010. Effects of multiple strengthening treatments on mechanical properties and stability of nanoscale precipitated phases in an alumi-numÀcopperÀlithium alloy. J. Mater. Sci. Technol. 26, 1078À1082. Ahmed, M., 1987, Correlation between aging heat treatments, microstructure and stress corrosion properties of AlÀLiÀCuÀMg alloys.

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