Dislocation distributions in an Al-4. 5% Mg alloy during superplastic deformation

Li, F; Roberts, W T; Bate, P S

doi:10.1016/0956-716X(93)90374-2

Title: Dislocation distributions in an Al-4. 5% Mg alloy during superplastic deformation

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Abstract

Superplasticity has been studied actively for several decades. Many models of the phenomenon have been proposed, in most of which normal dislocation glide has either not been considered or been considered only as an accommodation process to maintain continuity during grain boundary sliding. Although evidence of dislocation activity during superplastic deformation has been observed several times by TEM studies following deformation, the published results appear to be inconsistent and occasionally contradict themselves, and so are unable to provide systematic and convincing evidence for the development of any theoretical model. A major experimental problem associated with those results is the delay between unloading and quenching the specimens from the high testing temperatures. Dislocations can be lost by relaxation and annealing during the unloading and also during the preparation of TEM thin foils. A facility was developed to preserve the high temperature deformation microstructure for consequent TEM examination by quenching and aging under constant stress. This technique and some preliminary results are given elsewhere. The work presented here is from a more comprehensive TEM study of the dislocation distributions in an Al-4.5%Mg alloy developed during deformation at an elevated temperature and a range of strain rates.

Authors:

Li, F; Roberts, W T; Bate, P S ^[1]

Univ. of Birmingham (United Kingdom). IRC in Materials for High Performance Applications

Publication Date:: Fri Oct 01 00:00:00 EDT 1993

OSTI Identifier:: 6256090

Resource Type:: Journal Article

Journal Name:: Scripta Metallurgica et Materialia; (United States)

Additional Journal Information:: Journal Volume: 29:7; Journal ID: ISSN 0956-716X

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; ALUMINIUM BASE ALLOYS; DISLOCATIONS; MAGNESIUM ALLOYS; DEFORMATION; GRAIN BOUNDARIES; ALLOYS; ALUMINIUM ALLOYS; CRYSTAL DEFECTS; CRYSTAL STRUCTURE; LINE DEFECTS; MICROSTRUCTURE; 360102* - Metals & Alloys- Structure & Phase Studies

Citation Formats


                    Li, F, Roberts, W T, and Bate, P S. Dislocation distributions in an Al-4. 5% Mg alloy during superplastic deformation.  United States: N. p., 1993. 
        Web.  doi:10.1016/0956-716X(93)90374-2.

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                    Li, F, Roberts, W T, & Bate, P S. Dislocation distributions in an Al-4. 5% Mg alloy during superplastic deformation.  United States.  https://doi.org/10.1016/0956-716X(93)90374-2

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                    Li, F, Roberts, W T, and Bate, P S. 1993.  
        "Dislocation distributions in an Al-4. 5% Mg alloy during superplastic deformation".  United States.  https://doi.org/10.1016/0956-716X(93)90374-2.

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@article{osti_6256090,

  title        = {Dislocation distributions in an Al-4. 5% Mg alloy during superplastic deformation},

  author       = {Li, F and Roberts, W T and Bate, P S},

  abstractNote = {Superplasticity has been studied actively for several decades. Many models of the phenomenon have been proposed, in most of which normal dislocation glide has either not been considered or been considered only as an accommodation process to maintain continuity during grain boundary sliding. Although evidence of dislocation activity during superplastic deformation has been observed several times by TEM studies following deformation, the published results appear to be inconsistent and occasionally contradict themselves, and so are unable to provide systematic and convincing evidence for the development of any theoretical model. A major experimental problem associated with those results is the delay between unloading and quenching the specimens from the high testing temperatures. Dislocations can be lost by relaxation and annealing during the unloading and also during the preparation of TEM thin foils. A facility was developed to preserve the high temperature deformation microstructure for consequent TEM examination by quenching and aging under constant stress. This technique and some preliminary results are given elsewhere. The work presented here is from a more comprehensive TEM study of the dislocation distributions in an Al-4.5%Mg alloy developed during deformation at an elevated temperature and a range of strain rates.},

  doi          = {10.1016/0956-716X(93)90374-2},

  url          = {https://www.osti.gov/biblio/6256090},
  journal      = {Scripta Metallurgica et Materialia; (United States)},

  issn         = {0956-716X},

  number       = ,

  volume       = 29:7,

  place        = {United States},

  year         = {Fri Oct 01 00:00:00 EDT 1993},

  month        = {Fri Oct 01 00:00:00 EDT 1993}

}

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