Studies on Microstructure and High-Temperature (600–700 °C) Mechanical Stability of Ti–Al–Mn–Si Composite

It is well known that TiMn2-based alloys are widely used as high hydrogen storage materials. The purpose of this work was to study the temperature-dependent mechanical behavior of Ti–Al–Mn–Si composite in which the hexagonal Laves phase TiMn2 dominated. The role of β-Ti content in improving microstructure and high-temperature (600–700 °C) mechanical stability in terms of fracture toughness of the composite was also explored. Ti–Al–Mn–Si composite was prepared by melting in a vacuum induction furnace. The X-ray diffraction analysis of Ti–Al–Mn–Si composite revealed two phases, namely β-Ti and TiMn2. The phase fractions were as follows: β-Ti (18.26 wt%), TiMn2 (81.74 wt%). Therefore, the last one dominated in material microstructure, and this was confirmed by the scanning electron microscopy analysis. Beam specimens were cut from ingots, ground, and polished. Single-edge notch beam fracture toughness test of specimens was performed in a temperature range of 20 to 700 °C. It was revealed that fracture toughness of the composite is in a strong relation to its microstructure and phase composition. In particular, high-temperature (600–700 °C) mechanical stability was attributed to the appropriate failure micromechanism. Therefore, the studied Ti–Al–Mn–Si composite is promising in terms of fracture toughness for high-temperature applications.