KIMURA Kohei Tohoku University Graduate School of Dentistry Division of Fixed Prosthodontics, Professor, 大学院・歯学研究科, 教授 (40108551)
KIKUCHI Masafumi Tohoku University Graduate School of Dentistry Division of Dental Biomaterials, Assistant Professor, 大学院・歯学研究科, 助手 (50250791)
TAKADA Yukyo Tohoku University Graduate School of Dentistry Division of Dental Biomaterials, Assistant Professor, 大学院・歯学研究科, 助手 (10206766)
KATAKURA Naoyuki Tohoku University Graduate School of Dentistry Division of Dental Biomaterials, Associate Professor, 大学院・歯学研究科, 助教授 (70005031)
|Budget Amount *help
¥14,300,000 (Direct Cost: ¥14,300,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2000: ¥11,000,000 (Direct Cost: ¥11,000,000)
The purpose of this study was to evaluate the grindability of experimental titanium alloys with the hope of developing titanium alloys with better machinability than CP Ti for dental CAD/CAM applications. Experimental Ti-Ag alloys (5,10,20 mass% Ag), Ti-Cu alloys (2,5,10 mass%Cu) and Ti-Nb alloys (2,5,10,15,20,25,30 mass%Nb) were made by melting sponge titanium and pieces of silver, copper or niobium in an argon-arc melting furnace. The alloys were cast into a magnesia mold using a dental gas-pressure titanium casting machine. Cast alloy specimens (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layers (250 um) were removed, were ground using a SiC abrasive wheel on an electric handpiece at five circumferential speeds (500,750,1000,1250, or 1500 m/mm) with 100 gf. Grindability was evaluated by measuring the amount of metal volume removed after grinding during one minute.
At the lowest grinding speed (500m/min), there was no statistical difference among the grindability of the Ti-Cu alloys, Ti-Ag alloys and CP Ti. The grindability of the alloys increased as the grinding speed increased. At 1000 and 1250 m/min, the grindability of the 20% Ag and 10% Cu alloys were higher than that of CP Ti. At the highest grinding speed (1500 m/min), the grindability of the 20%Ag, 5%Cu and 10%Cu alloys were higher than that of CP Ti. The grindability at 1500m/min for the 10%Cu was about 2.9 times as large as that for CPTi. In the case of Ti-Nb alloys, the grindability of Ti-30%Nb alloy was about 2 times as large as that of CP Ti at the lower grinding speed (500 and 750m/min).
It was found that the grindability of the titanium was improved by alloying with silver, copper and niobium. The Ti-Cu alloys showed higher grindability at lower content of an alloying element than the Ti-Ag alloys.