Mechanical properties of a Mg–10 (vol.%)Ti composite

The present work deals with determination of the mechanical properties in the temperature range of 25 to 300 °C of a Mg–10(vol.%)Ti composite. The composite material was processed through powder metallurgical route by mixing pure titanium and magnesium powders followed by hot extrusion. Titanium reinforcement after extrusion presents two different morphologies: highly deformed small elongated particles and practically non-deformed coarse particles. The latter results from large titanium particles or aggregates of Ti particles, which practically did not deform during the extrusion. In addition, fine magnesium oxide particles, less than 1 μm, decorating original boundaries of magnesium particles are present. The mechanical properties at different temperatures were studied by tensile and jump strain rate tests. Although the magnesium matrix shows a relatively large grain size, the composite shows a high strength (160 MPa), with a high elongation at room temperature (8%), higher than most of ceramic reinforced magnesium composites. The stress exponent calculated in the 100–300 °C temperature range was about 13 indicating that the deformation is dominated by dislocation slip. Titanium particles strengthen the matrix by load transfer that is manifested by fracture of titanium particles. Furthermore, progress of cracks throughout hard titanium particles results in an increase of the ductility, since propagation of the crack is delayed or even arrested. The effectiveness of titanium reinforcement decreases with increasing the temperature.