Grindability of cast Ti-Cu alloys.
OBJECTIVE
The purpose of the present study was to evaluate the grindability of a series of cast Ti-Cu alloys in order to develop a titanium alloy with better grindability than commercially pure titanium (CP Ti), which is considered to be one of the most difficult metals to machine.


METHODS
Experimental Ti-Cu alloys (0.5, 1.0, 2.0, 5.0, and 10.0 mass% Cu) were made in an argon-arc melting furnace. Each alloy was cast into a magnesia mold using a centrifugal casting machine. Cast alloy slabs (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layer (250 microm) was removed, were ground using a SiC abrasive wheel on an electric handpiece at four circumferential speeds (500, 750, 1000, or 1250 m/min) at 0.98 N (100 gf). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1min. Data were compared to those for CP Ti and Ti-6Al-4V.


RESULTS
For all speeds, Ti-10% Cu alloy exhibited the highest grindability. For the Ti-Cu alloys with a Cu content of 2% or less, the highest grindability corresponded to an intermediate speed. It was observed that the grindability increased with an increase in the Cu concentration compared to CP Ti, particularly for the 5 or 10% Cu alloys at a circumferential speed of 1000 m/min or above.


CONCLUSIONS
By alloying with copper, the cast titanium exhibited better grindability at high speed. The continuous precipitation of Ti(2)Cu among the alpha-matrix grains made this material less ductile and facilitated more effective grinding because small broken segments more readily formed.
Division of Dental Biomaterials, Department of Oral Rehabilitation and Materials Science, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, 980-8575, Sendai, Japan. kikuchi@mail.cc.tohoku.ac.jp
Masafumi
M
Kikuchi
Yukyo
Y
Takada
Seigo
S
Kiyosue
Masanobu
M
Yoda
Margaret
M
Woldu
Zhuo
Z
Cai
Osamu
O
Okuno
Toru
T
Okabe
D017554:Carbon Compounds, Inorganic; D003300:Copper; D003722:Dental Alloys; D003735:Dental Casting Technique; D003775:Dental Polishing; D008422:Materials Testing; D008669:Metallurgy; D008855:Microscopy, Electron, Scanning; D017655:Silicon Compounds; D013499:Surface Properties; D014025:Titanium
D017554:Carbon Compounds, Inorganic; D003722:Dental Alloys; D017655:Silicon Compounds; D003300:Copper; D014025:Titanium; C022088:silicon carbide