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Synthesis of Intermetallic Aluminides by Explosive Reaction Pressing

 
: Prümmer, R.; Kochsiek, D.; Brunold, A.

Metall 49 (1995), No.3, pp.168-172
ISSN: 0026-0746
English
Journal Article
Fraunhofer EMI ()
explosive Direktverdichtung; explosive powder compaction; explosive reaction pressing; Flüssigphasenintern; gaseous; gasförmig; intermetallic aluminide; intermetallic reaction; intermetallische Reaktion; liquid phase sintering; Oberflächenanschmelzung; Preßling; shock compression; shock wave; sintering; stöchiometrische Mischung; stoichiometric mixture; Stoßwellenverdichtung; surface melting

Abstract
Shock compression of metal powders can cause good interparticle bonding and phase transformations. Surface melting leads to liquid phase sintering. Between dissimilar powders, chemical reactions can occur as a result of the high energy shock wave passing through the material. In this study, shock compression experiments have been performed on stoichiometric mixtures of nickel and aluminium as well as of titanium and aluminium powders, with the aim of synthesising intermetallic materials. The experimental method was direct explosive powder compaction. Completely reacted, intermetallic NiAl,TiAl3 and TiAl were obtained. It has been found that for each powder mixture, a certain individual threshold pressure has to be exceeded in order to initiate the intermetallic reaction. Microstructural investigations reveal that the reacting material melts completely during the exertion of the explosive pressure and solidifies rapidly after the passage of the shock wave. Pores caused by gaseous reacti on products are observed in the NiAl and TiAl3 compacts. All recovered specimens show strongly increased hardness and good consolidation.

: http://publica.fraunhofer.de/documents/PX-35515.html