Composites consisting of a pure Al matrix reinforced with a continuous network of 20 or 30 vol % of continuous fibres of Inconel 601 exhibit a tensile ductility of more than 10%, The fibre orientation distribution presents transverse isotropy with low misorientation with respect to the isotropy plane. The evolution of phase stresses during in-plane tensile testing was investigated by neutron diffraction, using Al-111 signal for the matrix and Ni-111 signal for the fibres. The phase stresses were obtained using computed diffraction elastic constants. Analysis of the variation of the fibre stresses as a function of composite strain allowed distinguishing four successive regimes corresponding to different straining behaviours of the phases.