Thermal cycling induced deformation and damage in Mo-fiber reinforced aluminum composites

Unidirectional Mo-fiber reinforced aluminum composites were subjected to th ermal cycling tests. The axial length of the composite increases with incre asing thermal cycles. The Mo fibers remain intact and the interfacial react ion between fiber and matrix is insignificant after thermal cycling. To rel ax the internal stress built up in the composite due to differential therma l expansion of the composite constituents, cracks are developed along the f iber-matrix interface and propagate into the aluminum matrix. The formation of interfacial cracks causes reduced density with increasing thermal cycle s. Thermally cycled specimens also show reduced tensile strength, which cou ld be related to the presence of interfacial cracks in the composite. (C) 1 999 Elsevier Science S.A. All rights reserved.