Composites Engineering. Vol. 4, No. 12, pp. 1241-1255. 1994 Copyright 0 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0961.9526/94 $7.00+ .oO Pergamon 096%9526(94) EOOO73-5 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSR UNIAXIAL CREEP OF LONG FIBRE REINFORCED METAL MATRIX COMPOSITES J. F. Durodola,‘* C. Ruiz“ and B. Derbyb ‘Department of Engineering Science, *Department of Materials, University of Oxford, Parks Road, Oxford 0X1, U.K. (Received 21 March 1994; zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJ final version accepted 1 July 1994) Abstract-A generalisation of McLean’s (Directionally Solidified Materials for High Temperature Service, 1983, The Metals Society, London) uniaxial creep model which accounts for the effects of inherent residual stresses, matrix primary creep and the treatment of the effect of possible instantaneous matrix yield upon loading is presented. The model and numerical micromechanics approach are used to analyse the uniaxial creep of Ti-6AI-4V/SiC metal matrix composites. Excellent agreement is obtained between the analytical and numerical models and predicted results are in reasonable agreement with published experimental results. NOTATION zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLK C f” n s’ T V 6” E’ u zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA V 00 elasticity constitutive tensor Young’s modulus hardening law (eqn (4)) creep law exponents deviatoric stress tensor time temperature volume fraction thermal coefficient of expansion Kronecker delta strain tensor in eqns (l)-(8); direct axial strain component in eqns (lo)-(30) deviatoric strain tensor stress tensor in eqns (l)-(8); direct axial stress component in eqns (lo)-(30) plastic multiplier Poisson’s ratio infinity Subscripts 1,2 creep stress and time exponents, respectively c, f,m composite, fibre and matrix i, j, k, I = 1,2,3 material axes directions 0 initial strain R residual Y yield point Left and right superscripts equivalent c, e, p, 0 creep, elastic, plastic and thermal t time A increment 1. INTRODUCTION The use of predictive methods for the estimation of creep of metal matrix composites such as Ti-6-WSiC based on the properties of the titanium alloy Ti-6Al-4V and the reinforcing silicon carbide, Sic, fibre is helpful for the design and lifting analysis of high *Present address: Oxford Brookes University, School of Engineering, Gypsy Lane Campus, Headington, OX3 OBP. 1241