Effect of In-Situ TiB2 Particles on the Creep Properties of 3 Wt.% TiB2/Al-Cu-Mg-Ag Composite

In this study, an in-situ 3 wt.% TiB 2 /Al-Cu-Mg-Ag composite was successfully fabricated by the salt-reaction method. The elevated temperature creep behaviour of Al-Cu-Mg-Ag matrix alloy and composite at 180–220°C under applied stresses of 150–275 MPa was investigated. The results showed that in-situ TiB 2 particles greatly refined the grain size and improved the elevated temperature creep properties of composite. Compared with the matrix alloy, the steady creep rates of the composite were 45–320% lower than those of the matrix alloy, and the composite exhibited lower creep strain and longer creep life under the same creep conditions. The better creep behaviour of composite was attributed to the reinforcing effect of TiB 2 particles and plenty of θ′ precipitates with small diameters in the composite. The true stress exponent of both the matrix alloy and composite is 5, indicating that their creep mechanism can be attributed to the dislocation climb mechanism.