                                                   !"   # $# $  %  &&  ’        ( ( %) *+ & &&&,    ’   !   $    &&-   ’ !"#$%  ,.$/0  1 2/3 4 3% 4  The microstructure of Ti6Al4V-SiC f composite, in as-fabricated condition and after long- term heat treatments (up to 1,000 hours) in the temperature range 400 - 600 °C, has been investigated by means of high-temperature X-ray diffraction (HT-XRD), energy dispersion spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Particular attention was paid to the strains, arising during heating, and to the micro-chemical evolution of fibre-matrix interface. Micro-chemical examinations evidenced that a thin TiC layer has formed between the fibre carbon coating and the matrix during the fabrication process. TiC slows down further diffusion of carbon towards the matrix and guarantees the interface stability also for the most severe treatments examined here.  The Ti6Al4V-SiC f composite is a promising material for applications in aeronautical engines. It has been fabricated at the C.S.M. laboratories in Castel Romano (Rome) by Hot Isostatic Pressing (HIP) process of Ti6Al4V sheets alternated with fiber layers. The samples of this material have been submitted to an extensive microstructural and mechanical characterization in as-fabricated condition and after long-term heat treatments with exposure time up to 1,000 hours at temperatures ranging from 400 to 600 °C (see Table 1), corresponding to the foreseen working condition in aeronautical turbines. Table 1. Heat treatments of the composite. The results of microstructural investigations carried out by means of HT-XRD (X-ray diffraction at high temperature), EDS (Energy Dispersion Spectroscopy), XPS (X-ray Photoelectron Spectroscopy) and AES (Auger Electron Spectroscopy) are reported here, while a companion paper [1] describes the mechanical behaviour. Some preliminary data have been already published in [2- 4].   400 400 400 600 600 600    100 500 1,000 100 500 1,000 Materials Science Forum Vols. 604-605 (2009) pp 331-340 online at http://www.scientific.net © (2009) Trans Tech Publications, Switzerland All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 160.80.88.249-01/09/08,16:19:04)