Authors: Y.H. Jeong, H.C. Choe, Y.M. Ko, S.J. Park, D.K. Kim and W. Brantley
Affilation: Chosun University, Korea
Pages: 721 - 724
Keywords: nano-structure, mechanical property, Ti-Hf alloy, dental implant
Objectives: Cp-Ti has a excellent biocompatibility. So, it was widely used dental implants and artificial joint. But it is not strong enough for some dental applications. Since Hf belongs to the same group as Ti in the periodic table of elements, Ti alloyed with this element will likely have good mechanical properties. The Ti-Hf alloy system forms an - isomorphous system and does not form any intermetallic compounds, which is also beneficial for good mechanical properties. The aim of this study was the improvement of mechanical property and biocompatibility by Hf addition to Ti-alloy. Methods: Ti-Hf(10, 20, 30 and 40wt%) alloys manufactured by non consumable vacuum arc melting furnace. All the specimens were nano-structure controlled by heat treatment at 1000oC for 24hr in Ar atmosphere followed by furnace cooling and quenching into 0oC water, respectively. Phase constitutions and microstructure of the samples were characterized by XRD, OM, SEM and EDX. Mechanical properties investigated using micro-hardness and tensile tester. Result: From SEM results, lamellar structure was transformed to needle-like structure with increased Hf contents. Especially, the microstructure of water quenched Ti-Hf specimens more fine than furnace cooled specimen. As a result of XRD, -phase peaks were detected for all samples. From hardness test, hardness and tensile strength of Ti-Hf alloy showed significantly increased as Hf content increased in the case of both water quenched and furnace cooled sample. For hardness and tensile strength value of water quenched sample had higher than those of furnace cooled sample. Especially, the hardness and tensile strength of water quenched Ti-40Hf alloy was higher than that of others due to formation of needle-like structure. Conclusion: The Ti-Hf(10, 20, 30 and 40wt%) alloys showed needle-like structure. After mechanical properties test, water quenched Ti-40wt%Hf alloy showed a excellent mechanical properties.
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