Preparation of lightweight, high hardness multi-component systems induced by partial oxidation and hard intermetallic phase formation

The ternary Mg-Al-Ti and quaternary Mg-Al-Ti-Cu systems were prepared by mechanical alloying in oxygen-lean atmosphere followed by spark plasma sintering. The ternary Mg-Al-Ti and quaternary Mg-Al-Ti-Cu systems which were sintered at 750 degrees C after 16 h milling showed the highest hardness of 509 and 947 HV with low densities of 2.9 and 3.9 g/cm3, respectively. The decrease in particle size and uniform dispersion of elements through optimization of the MA process induced the formation of uniform composite microstructure after SPS. Moreover, the addition of the fourth element, Cu, showed a significant impact on the improvement in hardness. This result was explained from the perspective of the microstructure and the electronic nature of elements. Our results provide a facile method for synthesizing oxide/metal composites from elemental powders without a separate oxidation process.

Automated summary

Ternary and quaternary composites of Mg-Al-Ti and Mg-Al-Ti-Cu systems were successfully prepared using mechanical alloying and spark plasma sintering. The optimized process resulted in uniform composite microstructure, and the addition of Cu significantly improved the hardness.