AlMgB14–TiB2 synthesized by a two-step heat-treatment method

Highlights: • AlMgB14–TiB2 was synthesized by the two-step heat treatment. • AlMg6B14–xTiB2 shows a significantly improved critical current density. • The grain size of AlMgB14 decreases with increasing Ti doping content. • The stepwise synthesis method can produce practical AlMgB14–TiB2 materials. -- Abstract: Superhard materials AlMgB14–xTiB2 disks were synthesized by a two-step heat-treatment method. In the first step, AlMg6B14–xTiB2 disks were fabricated by uniformly mixed Mg, B, Al powders and different contents Ti powder, and then AlMg6B14–xTiB2 disks were heated at 850 °C for 2 h in closed argon atmosphere. In the second step, AlMg6B14–xTiB2 disks were sintered at 1050 °C for half an hour in vacuum, then target AlMgB14–xTiB2 disks were obtained. The phase, microstructure and superconductivity were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and superconducting quantum interference device (SQUID). The nano-scale TiB2 particles as the second phase induced by Ti doping are uniformly distributed in the sample matrix. The results reveal that the stepwise synthesis method can produce practical AlMgB14–TiB2 materials