Development of 3D bicontinuous metal–intermetallic composites through subsequent alloying process after liquid metal dealloying

This study presents a novel process for the fabrication of metal–intermetallic composites with a 3D bicontinuous structure, achieved through a combination of liquid metal dealloying (LMD) and subsequent alloying. Initially, porous Ti structures are produced using the LMD process, followed by immersion in a molten Mg–3Al (wt%) metal. Due to the higher thermodynamic miscibility of Al with Ti compared to Mg, the concentration of Al in the Ti matrix increases as the immersion time increases. This results in a sequential phase transition within the Ti matrix: α-Ti → Ti₃Al → TiAl. The phase transition considerably affects the hardness and strength of the composite material, with the Mg–Ti₃Al–TiAl composite exhibiting a maximum hardness nearly twice as high as that of the conventional Mg–Ti composite. This innovative process holds potential for the development of various bicontinuous metal–intermetallic composites.