• 대한치과기공학회지
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• 제21권1호
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• pp.43-53
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• 1999

The mechannical properties and corrosion resistance of alloy added commercially pure titanium for dental implants have been investigated. Ti, To-65Zr, Ti-10.1Ta and Ti-17Sn alloys were melthed in arc furnace and the corrosion resistance of Ti alloys was evaluated by anodic polarization test. The microstructure and mechanical properties of Ti alloy were analysed by optical micrograph. hardness tester and instron. In isothermal test, Ti-10.1Ta and Ti-17Sn alloys exhibited the best oxidation resistance below $1100^{\circ}C$. Ti65Zr, Ti-10.1Ta and Ti-17Sn alloys showed better rockwell hardness compared with commercially pure. Ti As the result of the anodic polarization test in 5%HCl, it 5%HCl, it was known knows that Ti-65Zr, alloy showed a rapid decrease in current density at higher potenial in comparision with other Ti alloys.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.360-362
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• 2007

• 대한치과기공학회지
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• 제31권4호
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• pp.31-36
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• 2009

This study evaluated the grindability of series of Ti-Cu alloys in order to develop a Ti alloy with better grindability than commercially pure titanium(CP Ti). Experimental Ti-Xwt%Cu alloys(X=2, 5, 10) were made in an argon-arc melting furnace. Slabs of experimental alloys were ground using a SiC abrasive wheel on an electric handpiece at circumferential speed(15000, 30000rpm) by applying a force(250, 300gr). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 2 minutes. Data were compared to those for CP Ti and Ti-6wt%Al-4wt%V alloy. From results, It was observed that the grindability of Ti-Cu alloys increased with an increase in the Cu concentration compared to CP Ti, particularly the 10wt%Cu alloy exhibited the highest grindability at all speeds. By alloying with Cu, the Ti exhibited better grindability at high speed. The continuous precipitation of $Ti_2Cu$ among the ${\alpha}$-matrix grains made this material less ductile and facilitated more effective grinding because small segments more readily formed. The Ti-10wt%Cu alloy has a great potential for use as a dental machining alloy.

• Journal of Periodontal and Implant Science
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• 제27권2호
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• pp.329-346
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• 1997

Dental implants have been developed for enhancement of osseointegration. Biocompatibility, bone affinity and surface characteristics of dental implants are very important factors for osseointegration. The aim of the present study was to determine the cytotoxicity and the bone affinity of titanium phosphide(Ti-P) implant material. The Ti-P surface was obtained by vacuum sintering of titanium within compacted hydroxyapatite powder. The composition and the chemical change of the surface were determined by Auger electron spectroscopy. The in vitro cytotoxicity was evaluated by the viability of the bone cells and macrophages obtained from chicken embryo and rat,s peritonium, respectively. For the comparative evaluation, 316L stainless steel, commercially pure titanium and Ti-P materials, prepared in size of 1O.0mm in diameter and 5.0mm in height, were immersed separately in bone cells and macrophages for 10 days. For the evaluation of the in vivo bone affinity, 316L stainless steel, commercially pure titanium and Ti-P materials, prepared in size of 5.0mm in diameter and 10.0mm in length, were implanted after drilling in diameter 5.5mm in femurs of 2 dogs weighing 10Kg more or less. Six weeks after implantation the specimens were prepared for histopathological examination and were observed under light microscope. In comparison of in vitro bone cell viability, Ti-P and commercially pure titanium groups were not significantly different from control group (p>O.1), but 316L stainless steel group was significantly lower than control group(p<0.05). There was no statistical difference in the viability of macrophages between 3 different groups and control group(p>O.l). In comparison of in vivo study, 316L stainless steel and commercially pure titanium showed fibrous encapsulation, but Ti-P showed remarkable new bone formation without any fibrous tissue. The results demonstrate that Ti-P has favorable biocompatibility and bone affinity, and suggest that dental implants with Ti-P surface may enhance osseointegration.

• 대한기계학회논문집A
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• 제27권7호
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• pp.1152-1158
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• 2003

The mechanical behavior of a commercially pure titanium (CP-Ti) is investigated at high temperature Split Hopkinson Pressure Bar (SHPB) compression test with high strain-rate. Tests are performed over a temperature range from room temperature to 1000$^{\circ}C$ with interval of 200$^{\circ}C$ and a strain-rate range of 1900 ∼ 2000/sec. The true flow stress-true strain relations depending on temperature are achieved in these tests. For construction of constitutive equation from the true flow stress-true strain relation, parameters for the Johnson-Cook constitutive equation is determined. And the modified Johnson-Cook equation is used for investigation of behavior of flow stress in vicinity of recrystalization temperature. The Modified Johnson-Cook constitutive equation is more suitable in expressing the dynamic behavior of a CP-Ti at high temperature, i.e. about recrystalization temperature.

• 대한치과보철학회지
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• 제39권1호
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• pp.84-95
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• 2001

Titanium is widely used in dentistry for its low density, high strength, fatigue resistance, corrosion resistance, and biocompatibility. But it has a tendency of surface damage under circumstance of friction and impact for its low hardness of the surface. Coating is one of methods fir increasing surface hardness. Its effect is to improve surface physical characteristics without change of titanium. Diamond-like carbon and titanium nitride are known for its high hardness of the surface. So that this study was aimed at the wear test and the cytotoxicity test of the commercially pure titanium and Ti-6Al-4V alloy which were deposited by diamond-like carbon film or titanium nitride film to acertain improvement of the surface hardness and the biocompatibility. A disk (25mm diameter, 2mm thickness) was made of commercially pure titanium and Ti-6Al-4V alloy and these substrates were deposited by diamond-like carbon film or titanium nitride film. Diamond-like carbon film was deposited by the method of radiofrequency plasma assisted chemical vapor deposition and titanium nitride film was deposited by the method of reactive arc ion plating. Then these substrates were tested about wear characteristics by the pin-on-disk type wear tester in which ruby ball was used as a wear causer under the load of 32N, The fracture cycles were measured by rotating the substrates until their films were fractured. The wear volume was measured after 150 cycles and 3,000 cycles using surface profiler. The cytotoxicity test was peformed by the method of the MTT assay. The results were as follows : 1. In the results of the wear volume test, commercially pure titanium and titanium alloy which were coated by diamond-like carbon film or titanium nitride aim had higher resistance against wear than the substrates which were not coated by any films (P<0.05). 2. In the results of the fracture cycle test and the wear volume test, diamond-like carbon film had higher resistance against wear than titanium nitride film (P<0.05). 3. In both coatings of diamond-like carbon aim and titanium nitride film, Ti-6Al-4V alloy had higher resistance against wear than commercially pure titanium (P<0.05) 4. In the results of the cytotoxicity test, diamond-like carbon film and titanium nitride film had little cytotoxicity as like commercially pure titanium or Ti-6Al-4V alloy (P>0.05).

• 한국분말재료학회지
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• 제25권4호
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• pp.327-330
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• 2018

This study is conducted as a preliminary research to verify the feasibility of Ti-based Oxide dispersion strengthened (ODS) alloy. Pure-Ti powder is mixed with $Y_2O_3$ powder and subsequently, mechanically alloyed at $-150^{\circ}C$. The Ti-based ODS powder is hot-isostatically pressed and subsequently hot-rolled for recrystallization. The microstructure consists of elongated grains and Y excess fine particles. The oxide particle size is larger than that of the typical Fe-based ODS steel. Tensile test shows that the tensile ductility is approximately 25%, while the strength is significantly higher than that of pure Ti. The high-temperature hardness of the Ti-ODS alloy is also significantly higher than that of pure Ti at all temperatures, while being lower than that of Ti-6Al-4V. The dimple structure is well developed, and no evidence of cleavage fracture surface is observed in the fracture surface of the tensile specimen.

• 대한치과기공학회지
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• 제33권4호
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• pp.263-270
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• 2011

Purpose: The grindability of binary Ti-X%Zr(X=10,20,40) alloys in order to develop a Ti alloy with better machinability than unalloyed titanium has been evaluated. Methods: Experimental Ti-Zr alloys were made in an argon-arc melting furnace. Slabs of experimental alloys were ground using a SiC abrasive wheel on an electric handpiece at circumferential speeds(12000,18000,25000 or 30000rpm) by applying a force(200gr). Grinding rate was evaluated by measuring the amount of metal volume removed after grinding for 1 minute and the volume ratio of metal removed compared to the wheel material lost, which was calculated from the diameter loss (grinding ratio). Experimental datas were compared to those for cp Ti(commercially pure titanium) and Ti-6%Al-4%V alloy were used controls. Results: It was observed that the grindability of Ti-Zr alloys increased with an increase in the Zr concentration. More, they are higher than cp Ti, particularly the Ti-20%Zr alloy exhibited the highest grindability at all circumferential speeds. There was significant difference in the grinding rate and grinding ratio between Ti-20%Zr alloy and cp Ti at any speed(p<0.05). Conclusion: By alloying with Zr, the Ti exhibited better grindability at all circumferential speeds. the Ti-20%Zr alloy has a great potential for use as a dental machining alloy.

• 대한치과기공학회지
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• 제35권4호
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• pp.295-302
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• 2013

Purpose: The grindability of Ti-10%Zr-X%Cr(X=0,1,3) alloys in order to develop Ti alloys for dental applications with better machinability than unalloyed titanium has been evaluated. Methods: Experimental Ti-10%Zr-X%Cr(X=0,1,3) alloys were made in an argon-arc melting furnace. Slabs of experimental alloys were ground using a SiC abrasive wheel on an electric handpiece at one of the four rotational speeds of the wheel (12000, 18000, 25000 or 30000rpm) by applying a force(100gf). Grindability was evaluated by measuring the amount of metal volume removed per minute(grinding rate) and the volume ratio of metal removed compared to the wheel material lost, which was calculated from the diameter loss (grinding ratio). Experimental datas were compared the results with those of cp-Ti(commercially pure titanium) Results: It was observed that the grindability of Ti-10%Zr-X%Cr(X=0,1,3) alloys increased with an increase in the Cr concentration. More, they are higher than cp-Ti, particularly the Ti-10%Zr-3%Cr alloy exhibited the highest grindability at all rotational speeds except 12000rpm. There was significant difference in the grinding rate and grinding ratio between Ti-10%Zr-3%Cr alloy and cp-Ti at all rotational speeds(p<0.05). Conclusion: The Ti-10%Zr-3%Cr alloy exhibited better grindability at high rotational speeds, great potential for use as a dental machining alloy.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.143-160
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• 1996

The purpose of this study was to evaluate the response in aspect of attachment and growth rate of osteoblasts and growth rate of osteoblasts and human gingival fibroblasts to the commercially pure titanium(CP titanium)and titanium alloy(Ti-6AI-4V) that are used widely as implant materials, and to obtain the basic information to ideal implant materials. In the studly, commercially pure titanium in first test group, titanium alloy(Ti-6AI-4V) in second test group, cobalt-chrome-molybdenum alloy(Co-Cr-Mo alloy) in positive control group, and tissue culture polystyrene plate in negative control group were used. The results of this study were as follows. 1. Bone marrow cells cultured on CP titanium and Ti-6Al-4V showed significantly greater attachment and growth rate(p(0.05) compared to Co-Cr-Mo alloy in each time. 2. There were no significant differences(p>0.05) in attachment and growth rate of bone marrow cells cultured on CP titanium and Ti-6AI-4V or tissue culture plate. 3. Most bone marrow cells cultured on CP titanium, Ti-6Al-4V and tissue culture plate were attached well to each substratum in first 2days, and then, grew at higher growth rate. On the other hand, some cells cultured on Co-Cr-Mo alloy failed to attach in first 2 days, and then, attached cells grew at lower growth rate than other groups. 4. Attachment and growth rates of gingival fibroblasts cultured on CP titanium and Ti-6Al-4V showed no significant differences(p>0.05) compared to Co-Cr-Mo alloy in 2 days, but significantly greater increase(p<0.05) in 5 and 9 days. 5. There were no significantly differences(p>0.05) between growth rates on gingival fibroblasts cultured on CP titanium, Ti-6Al-4V and tissue culture plate in 2 and 5days, but a significant lower growth rate(p<0.05) on CP titanium and Ti-6Al-4V versus tissue culture plate. 6. Some gingival fibroblasts cultured on all specimen groups failed to attach, but attached cells grew well, especially on CP titanium, Ti-GAl-4V and tissue culture plate. 7. There were no significant differences(P>0.05) between growth rates of both bone marrow cells and gingival fibroblasts cultured on CP titanium and Ti-6AI-4V. As a result of this study, both commercially pure titanium and Ti-6AI-4V showed excellent biocompatibility and there was no significant difference in the cellular response to the both metals. Bone marrow cells cultured on each substratum showed significantly greater growth rate and responded sensitively to cytotoxic effects of metal surfaces compared to gingival fibroblasts. Considering cell response to the substrate, it was likely that the composition itself of titanium metals have no significant effect on the biocompatibility. Further study need to be done to evaluate the influence of surface characteristics on cellular responses.