Abstract: The main mechanism of rare-earth element Sc on the microstructure and properties of Zr–8.8Si biomaterial alloy was explored. The novel Zr–8.8Si–xSc (x?=?0, 5, 10 and 15 at. %) alloys were prepared by electric arc smelting with Ar protection. The microstructural and mechanical properties as well as electrochemical corrosion and tribological behaviors in artificial saliva solution of the Zr–8.8Si–xSc alloys were systematically studied. The results show that the Zr–8.8Si–xSc alloys only consist of two-phase α-Zr and Zr3Si, Sc dissolve in α-Zr matrix to form Zr–Sc solid solution. The addition of Sc is conducive to refine microstructure, and reduce micro-pores of Zr–8.8Si alloy which lead to higher Young's modulus, compressive strength and micro-hardness. Among them, the highest value of Young's modulus is 31.5 GPa, still at a low level in biomedical alloy. The promotion of corrosion resistance can be attributed to the addition of Sc which can accelerate the formation of passive film, slow down the appearance of pitting and reduce the accumulation of corrosion products in surface. Under the condition of sliding wear test with artificial saliva solution, compared with Zr–8.8Si–0Sc alloy, the wear loss of samples with Sc is greatly decreased, and wear resistance is increased with increasing content of Sc. The experimental results indicate that the combination of good mechanical properties, corrosion resistance and tribological properties of Zr–8.8Si–(5, 10 and 15 at. %) Sc alloys was much better than Zr–8.8Si–0Sc alloy. Among them, the comprehensive property of Zr–8.8Si–10Sc alloy is preferable in this work.

Key words: Zr–8.8Si–xSc alloys, Biomedical alloy, Microstructure, Mechanical properties, Corrosion resistance, Tribological properties