THE TRANSVERSE CREEP AND TENSILE BEHAVIOUR OF SCS-6/Ti-6Al-4V METAL MATRIX COMPOSITES AT 482°C

Abstract The tensile behaviour and the creep behaviour of SCS-6/Ti-6Al-4V composites in the transverse direction at 482°C were evaluated. The tensile strength of the transverse composite was 360 MPa; the unreinforced matrix strength was more than 600 MPa. Separation of the fibre-matrix interface was the primary cause for the transverse composite's low tensile strength. Creep tests were performed in air at 482°C over the stress range of 69 to 276 MPa. The composite was less creep-resistant than the matrix when tested at stress values higher than 150 MPa. Below 150 MPa, the creep-resistance of the composite and the unreinforced matrix were very similar. Finite element analyses were performed for a composite with an infinite, periodic, uniform fibre array and two different fibre-matrix interface strength assumptions. Two matrix material models were used: isotropic plasticity with steady-state creep, and the ‘viscoplasticity based on overstress’ unified theory. Both material models were able to represent the ...