생체용 Ti₁-x-Zrx합금의 기계적 성질과 내부식성 = Mechanical Properties and Corrosion Resistance of Ti₁_ｘ-Zrｘ Alloys for Biomedical Implants

다국어 초록 (Multilingual Abstract)

While titanium and its alloys has been well studied for a long time, new interest in these materials and their properties has arisen in recent years with respect to their application as biomedical metallic materials. For practical purposes, the following performances are essential for biomaterials.

(1) low specific gravity
(2) high corrosion resistance
(3) good biostability and biocompatibility
(4) sufficient mechanical properties
(5) non-toxicity

To develop biomedical implant materials having all the properties mentioned above, new titanium-zirconium alloys were prepared in this study. Mechanical properties and corrosion resistance were then investigated for as-cast and as-homogeneized Ti₁_x-Zrx alloys in order to reveal their possible use for biomaterials. From the experiments, the following results are obtained:

1. No martensite structure are observed in the specimens made of pure Ti and Zr. In contrast them, Ti-Zr alloys containing 18wt%Zr, 24wt%Zr and 48wt%Zr show a kind of martensite structure regardless heat treatment.
2. Fineness of structures for as-cast-alloys seems to vary with alloy composition. Ti-Zr alloy containing 48wt%Zr shows the finest microstructure.
3. Hardness of Ti-Zr alloys shows continuous change through the system and the
alloys containing 48 to 60wt%Zr indicate higher hardness compared with those of pure Ti and other alloys. It is well known that hardness is usually changed with
substitutional atoms, and effect of solute atom on hardness is greatest with an
equi-atomic composition. The greatest hardness which was obtained in Ti-Zr alloys containing 48 to 60wt%Zr is therefore reasonable. Also, enhanced hardness can be explained on elastic interaction between dislocation and substitutional solute atoms in crystal structure and on fineness of structure.
4. Pure Ti and Zr alloys containing 6wt%Zr, 12wt%Zr, 18wt%Zr, 36wt%Zr show better corrosion resistance compared with those of pure Zr, stainless steel(SUS 316L) and the Ti-Zr alloy containing 48wt%Zr.
5. Comparing hardness, microstructure and corrosion of Ti₁_x-Zrx alloys, no large differences between as-cast and as-homogenized alloys are seen.