TEM and HRTEM Characterization of TiAl Diffusion Bonds Using Ni/Al Nanolayers

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Sonia Simoes (Author) FEUP; Filomena Viana (Author) FEUP; Ana S Ramos (Author) Other; Maria T Vieira (Author) Other; Manuel F Vieira (Author) FEUP

Journal

Title: Microscopy and Microanalysis

Vol. 21 No. 1

Pages: 132-139

ISSN: 1431-9276

Publisher: Cambridge University Press

Indexing

ISI Web of Knowledge - 11 Citations

Scopus - 13 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

CORDIS: Technological sciences > Engineering > Materials engineering

Other information

Authenticus ID: P-00A-ANH

DOI: 10.1017/s1431927614013087

Abstract (EN): Diffusion bonding of TiAl alloys can be enhanced by the use of reactive nanolayer thin films as interlayers. Using these interlayers, it is possible to reduce the conventional bonding conditions (temperature, time, and pressure) and obtain sound and reliable joints. The microstructural characterization of the diffusion bond interfaces is a fundamental step toward understanding and identifying the bonding mechanisms and relating them to the strength of the joints. The interface of TiAl samples joined using Ni/Al nanolayers was characterized by transmission electron microscopy and scanning transmission electron microscopy. Microstructural characterization of the bond revealed that the interfaces consist of several thin layers of different composition and grain size (nanometric and micrometric). The bonding temperature (800, 900, or 1,000 degrees C) determines the grain size and thickness of the layers present at the interface. Phase identification by high-resolution transmission electron microscopy combined with fast Fourier transform and electron energy-loss spectroscopy analyses reveals the presence of several intermetallic compounds: AlTiNi, NiAl, and Al2TiNi. For bonds produced at 800 and 900 degrees C, nanometric grains of Ti were detected at the center of the interface.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8