No abstract

No abstract

Discontinuously reinforced aluminum alloys for elevated temperatures with a matrix hardened by intermetallic phases generally have to be produced by powder metallurgy because of their high content of alloying elements. The objective of this investigation was the evaluation of powder metallurgical processing for an A16Fe powder alloy containing various fractions and volume contents of Sic particles. During processing, the effect of powder mixing on S i c particle distribution in the extruded product was emphasized and examined by scanning and transmission electron microscopy. Gas development during mixing and degassing was investigated by mass spectroscopy and related to strength, fracture toughness and ductility. In addition to room temperature mechanical properties, elevated temperature tensile properties were evaluated for the various Sic particle distributions.

Metallurgists and casting engineers focused on new composites (DSE) for high temperature applications in jet engines. Some examples of reinforced superalloys are discussed. The phase stability of microstructures has been tested using a special high thermal gradient device. For stationary gas turbines efforts in alloy development, transfer of laboratory scale to precision casting technology, and first engine tests of directionally solidified Co-Cr,C, eutectic alloy are being reported.

Die Vorgänge beim Spannungsarmglühen von Ti6A14 V wurden mittels Elektronenmikroskopie und Zugversuchen untersucht. Bei 740 °C konnte bereits teilweise Rekristallisation beobachtet werden. Die Abkühlgeschwindigkeit von der Glühtemperatur hat einen ausgeprägten Einfluß auf Festigkeit und E‐Modul. Es wird angenommen, daß bei langsamer Abkühlung durch eine Erhöhung des Alpha‐Phasenanteils und insbesondere durch Ordnung des in relativ hoher Konzentration vorhandenen Sauerstoffs eine Aufhärtung erfolgt. In der Praxis sollte deshalb nach dem Glühen bis auf Temperaturen von etwa 300 °C relativ langsam abgekühlt werden.