Boom, G.

Bronsveld, P.M.

Hemmes, K.

Hosson, J.Th.M. De

Huis in 't Veld, A.J.

English

Proceedings - University of Groningen

   University of GroningenThe Interaction between Dislocations and Precipitates in Al-Li Alloys Studied by TEMHuis in 't Veld, A.J.; Hemmes, K.; Bronsveld, P.M.; Boom, G.; Hosson, J.Th.M. DeIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1984Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Huis in 't Veld, A. J., Hemmes, K., Bronsveld, P. M., Boom, G., & Hosson, J. T. M. D. (1984). TheInteraction between Dislocations and Precipitates in Al-Li Alloys Studied by TEM.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 12-10-2022Science Centre, Nijenborgh 18, 9747 AG Groningen, The Netherlands The superalloy Ma 6000 E is a Ni-base alloy developed for high creep resist- ance at intermediate as well as at high temperatures. The alloy has a complex composition being strengthened with sev- eral solid solution additions, y' pre- cipitates for intermediate temperature strength and inert yttria for extreme elevated temperature creep resistance. The volume fraction of the y' (Ni3Al) precipitates is approximately 50% and their size about 0.2 pm in diameter. The yttriumoxide (Y2O3) volume fraction is 2.9% with an average particle size of 28 nm. Precipitates in an as received sam- ple, deformed in tension to rupture at 760°C, are identified with an energy- dispersive X-ray system (EDS). Disloca- tion structures are studied using a 200 kV transmission electron microscope (JEM 200 cx). It is expected that dis- locations bypass the yttriumoxide par- ticles by looping, whereas y' precipi- tates can be bypassed either by loopinq or shearing. With increasing tempera- ture dislocations will tend to climb rather than form coplanar Orowan loops around the particles. The experimental results are compared with predictions based on a model calculation for the critical particle diameter where cutting is taken over by looping. THE INTERACTION BETWEEN DISLOCATIONS AND PRECIPITATES IN Al-Li ALLOYS STUDIED BY TEM A. J. Huis In 'T Veld, K. Hemmes, P. M. Bronsveld, G. Boom and J. Th. M. De Hosson Department of Applied Physics, University of Groningen, Materials Science Centre, Nijenborgh 18, 9747 AG Groningen, The Netherlands The basic strengthening mechanism of aluminium-lithium alloys is due to the formation of coherent 6' precipitates (ordered Li2 phase A13Li). The addi- tion of Li to Al results in a reduction of density and an increased modulus of elasticity compared with conventional aluminium alloys. Consequently, the development of Al-Li alloys is highly desirable for structural applications, especially in aerospace industry. In this paper, a transmission elec- tron microscopic study of the mechanism of dislocation motion in Al-2.2 wt% Li is presented. TEM micrographs were taken using a JEM 200 CX operating be- tween 120 and 160 keV. In order to obtain precipitates of different size, ageing times were varied from 1 hr to 115 hrs, and the ageing temperatures ranged between 200 and 245OC. Particle size distribution and volume fraction were determined using stereo-transmission electron mi- croscopy. The increase in yield stress as a function of the experiment- ally determined particle size distribu- tion and volume fraction can be predicted based on theoretical models. FROM BLANK TO CAN-- THE ORIGIN AND GROWTH OF THE MORPHOLOGY OF W. J. of THE WALL OF A DWI CAN Van Koesveld and Schade Van Westrum Hoogovens groep bv, IJmuiden, Research and development, product technology An extensive study of the morphology the wall of the two-piece drawn and wall-ironed (dwi-) can has been made by both SEM and EPMA. Both the topo- graphy and the distribution of tin on the inner and outer sides of the wall could be logically explained as a pro- duct of the various stages in the forming process of the can. It is sug- gested that the mechanical properties of the steel base and those of the coating material have a strong influ- ence on the resulting properties of the can wall. SOME APPLICATIONS OF ELECTRON MICROS- COPY IN THE AIRCRAFT INDUSTRY A. Kwakernaak and J. J. V. Konig Technological Centre, Fokker b.v., Schiphol, The Netherlands Important applications of electron microscopy in the aircraft industry are the characterization of surfaces after chemical pretreatments and the study of fracture surfaces of aircraft parts. Transmission electron micros- copy was used to study the structure of 

The Interaction between Dislocations and Precipitates in Al-Li Alloys Studied by TEM

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The Interaction between Dislocations and Precipitates in Al-Li Alloys Studied by TEM

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