Synthesis, processing and properties of nanophase aluminide

Chang, H L; Hofler, J.; Altstetter, C. J.; Averback, Robert S

doi:10.1016/b978-1-85166-822-9.50106-0

Cited by 1 publication

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High-temperature intermetallic compounds have shown promise over the last several decades as materials for use in modern aircraft, as high-temperature engine components, in shape-memory devices, and as lightweight structural supports. , One important drawback to their use is that most of these compounds are brittle at low temperatures. , It has been suggested that the brittleness arises from the nature of the metallic bonding in these intermetallics. , There have been various reports over the past decade for evidence of improved ductility in fine grained − or nanocrystalline − materials.…”

Section: Introductionmentioning

confidence: 99%

Rapid Solid-State Synthesis of Titanium Aluminides

et al. 2003

View full text Add to dashboard Cite

Intermetallics, such as the titanium aluminides, hold promise for high-temperature structural applications if their ductility can be improved by making fine-grained materials. An important step toward this goal is the rapid synthesis of finely divided powders via simple chemical processes. Here, single-displacement reactions between varying ratios of the metal halides TiCl 3 and AlCl 3 , utilizing Mg as a reducing agent, enables the rapid synthesis of Ti 3 Al, TiAl, and TiAl 3 upon initiation with a heated filament. Reaction temperatures and propagation rates are measured using in situ thermocouples and electrodes. This leads to insights into the propagation mechanism for intermetallic formation in these displacement reactions. Once the sublimation temperature of AlCl 3 (178°C) is reached, propagation accelerates rapidly. The reaction temperature exceeds 1000°C within 700 ms. Propagation velocities on the order of 0.5 mm/s are observed. Redox reactions that begin during propagation create electrical signals, which confirm that initiation of chemical processes occur upon the sublimation of AlCl 3 . Microwave heating was found to be another effective method to initiate these reactions and leads to the formation of phase pure TiAl which is not obtainable as a single product via filament initiation. Powders of TiAl 3 can also be produced through reactions between LiAl and TiCl 3 .

show abstract