The effect of the heat treatment of carbon fiber reinforced aluminium alloys (CFRM : two PAN based high modulus and a PAN based high strength CFs, V_f=70%) on the bending strength, the compressive strength and the interfacical shear strength between the carbon fibers and the matrix has been studied. The FRM samples were subjected to heat treatments in Ar gas at temperatures of 773K and 873K for from 3.6 ks to 90 ks to assess their mechanical properties and interface reactions. After the heat treatments, X-ray analysis revealed that the content of Al₄C₃ accumulated at the interface increased as already well known, and the interfacial shear strength increased to an extent according to the temperature and the holding time. As the interfacial shear strength of the PAN based high modulus carbon fiber/Al-7.8%Mg alloy FRM increases from a level of 5 MPa to a higher level of 25 MPa after the heat treatments, the tensile strength of the CFRMs decreases rapidly from a high level of 1, 200 MPa to a lower level of 550 MPa, however the compressive strength of the CFRMs shows no change. In the case of the PAN based high modulus carbon fiber/ Al 7.1%Si-0.36%Mg alloy FRMs, the tensile strength decreases slightly from a level of 600 MPa to a lower level of 500 MPa, on the contrary the compressive strength of the CFRMs shows sharp increase from a level of 600 MPa to a higher level of 900 MPa, as the interfacial shear strength of the FRMs increases from a level of 25 MPa to a higher level of 40 MPa after the heat treatments. The compressive strengths of the CFRMs contain high strength CFs show a high, constant level of 1, 600 MPa and the tensile strengths of the CFRMs show a low level of 450 MPa in the range of interfacial shear strengths over 40 MPa even after the heat treatments.

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Analytical predictions of the constitutive relations and the damping capacity of TiNi shape memory alloy (SMA) fiber embedded hybrid composite lamina have been presented. The stress induced martensitic (M-phase) and rhombohedral (R-phase) transformations of the TiNi SMA fiber are taken into account in the macro-mechanical constitutive modeling of SMA material. The constitutive relation of unidirectional SMA hybrid composites are derived based on the unit-cell micromechanics approach. The predictive capability of the present method is demonstrated by simulating the stress-strain curves under isothermal loading and unloading conditions. The specific damping capacity defined as the ratio of the hysteresis type energy dissipation to the stored strain energy is also numerically computed.

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