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COST 507 - Repositório Aberto da Universidade do Porto

COST 507 - Repositório Aberto da Universidade do Porto

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Experimental Investigations in Ternary and Quaternary Ti-Al-<br />

Metal Systems<br />

D8<br />

Erich Lugscheider, Klemens Schlimbach,<br />

Lehr- und Forschungsgebiet Werkstofrwissenschaften, RWTH Aachen, Germany<br />

Manfred Koschlig, Degussa AG, Hanau, Germany<br />

and<br />

Ingo Reinkensmeier, Eurobras GmbH, Menden, Germany<br />

Abstract<br />

This research forms part of the <strong>COST</strong> <strong>507</strong>-Π programme on the Ti-Al-Me-Me system<br />

(Key System 5). Within these work alloys of the system Ti-Al-Cu-Ni are investigated<br />

concerning its density, oxi<strong>da</strong>tion behaviour (825°C/15h), phase transition- and melting<br />

temperature for both conditions the molten and annealed state. Furthermore wetting -<br />

and joining tests were carried out on Ti 3 Al- and TiAl-base material with alloys which<br />

have a good oxi<strong>da</strong>tion behaviour and a suitable melting temperature.<br />

1 Introduction<br />

The intermetallic a 2 -Ti 3 Al and γ-TiAI alloys possess particular mechanical and<br />

physical properties which make them of interest for use as structural materials in the<br />

aerospace and aircraft industries. In contrast to conventional Ti based alloys, the<br />

Titaniumaluminides have a higher resistance to oxi<strong>da</strong>tion and exhibit significantly less<br />

sensitivity to hydrogen embrittlement. These materials are able to exceed the<br />

application temperature of advanced Ti-alloys and also have the potential to replace<br />

nickel-based superalloys up to 800°C. Brazing seems to be the most successful joining<br />

method for this materials because of its less process temperature. Hence, the influence<br />

of the base material by a brazing process is much smaller than by a welding process.<br />

For the development of new filler metals for TLAl-based materials the knowledge of<br />

the metallurgical reactions between the filler metal and the base material is an<br />

important aspect; a further feature is a detailed investigation of the filler metals<br />

themselves. This includes the determination of the phases with X-ray diffraction,<br />

thermal analysis (ascertain the phase transition temperatures and melting ranges),<br />

determination of density and metallografie investigations (light- and<br />

electronmicroscopy).<br />

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