Effects of alloying elements (X: Zr, Nb, Ta, Mo, and Si) in the (Ti47.5X2.5) Cu50 precursor alloy on the microstructure, mechanical properties, and corrosion resistance of 3D interconnected Mg-Ti composites synthesized using liquid metal dealloying

초록

The effects of alloying elements (X = Zr, Nb, Ta, Mo, or Si) on the microstructure, mechanical properties, and corrosion resistance of three-dimensional interconnected Mg-Ti composites synthesized using liquid metal dealloying (LMD) are systematically investigated. The (Ti47.5X2.5)Cu50 precursor alloys were immersed in a Mg-Ca (10 at.%) melt at 600 degrees C and 800 degrees C. Alloying additions substantially influenced the precursor microstructure and resulted in variations in the synthesized Ti ligament morphology, grain characteristics, and Ti phase crystal structures after LMD. Notably, the additions of Zr, Nb, and Ta promoted the formation of fine lamellar alpha-Ti grains, while Mo addition facilitated the formation of beta-Ti grains at 800 degrees C. The Zr-added composite exhibited superior mechanical properties and achieved the highest yield strength and work-hardening rate due to uniform load transfer and reduced localized plastic deformation, according to the predictions of the microstructure-based finite-element method. Conversely, Nb, Ta, Mo, and Si negatively affected yield strength due to the reduced Ti fractions and ineffective ligament morphologies. The corrosion resistance in a 0.6 M NaCl solution was improved by adding Zr, Nb, Ta, and Mo, with Zr exhibiting the highest resistance. In contrast, the addition of Si reduced corrosion resistance, primarily owing to an increased interphase area, which was approximately 14 % higher than that of the non-alloyed composite. These findings provide key insights into the optimization of Mg-Ti composites for advanced biomedical applications, emphasizing the role of alloying strategy in achieving tailored mechanical and chemical performance.

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