TY - GEN
T1 - Grain refinement in α+β-type Ti-4. 5Al-6Nb-2Fe-2Mo alloys through precipitation of TiB or rare earth oxides
AU - Kimura, Yasunori
AU - Umetsu, Nobuyuki
AU - Iwata, Naomichi
AU - Nakaoka, Shinichiro
AU - Ueda, Kyosuke
AU - Narushima, Takayuki
PY - 2012/12/1
Y1 - 2012/12/1
N2 - The β-grain growth in biomedical α + β-type Ti-4. 5Al-6Nb-2Fe-2Mo (mass%) alloys with the addition of small amounts of rare earth metals such as La, Y, Ce, and Er and boron was investigated in the β region of the alloys at temperatures of 1173-1573 K. The addition of Er (0.1 mass%), La (0. 01mass%), and Y (0.1 mass%) suppressed the β-grain coarsening up to heating temperatures of 1273, 1373, and 1473 K, respectively; however, this effective suppression of grain growth was not observed in the Ce-added (0.1 mass%) alloy. The marked β-grain refinement in the Y-added alloy appears to be caused by the relatively high stability of the Y2O3 precipitate at high temperatures compared with other rare earth metal oxides. The addition of 0. 003 - 0. 03mass% boron was effective in suppressing the β-grain growth, where the effectiveness depended on the content of boron. An increase in the boron content extended the effective temperature range for β-grain growth suppression. The TiB precipitates were rod-shaped elongated along the forging direction in the β matrix or small round-shaped.
AB - The β-grain growth in biomedical α + β-type Ti-4. 5Al-6Nb-2Fe-2Mo (mass%) alloys with the addition of small amounts of rare earth metals such as La, Y, Ce, and Er and boron was investigated in the β region of the alloys at temperatures of 1173-1573 K. The addition of Er (0.1 mass%), La (0. 01mass%), and Y (0.1 mass%) suppressed the β-grain coarsening up to heating temperatures of 1273, 1373, and 1473 K, respectively; however, this effective suppression of grain growth was not observed in the Ce-added (0.1 mass%) alloy. The marked β-grain refinement in the Y-added alloy appears to be caused by the relatively high stability of the Y2O3 precipitate at high temperatures compared with other rare earth metal oxides. The addition of 0. 003 - 0. 03mass% boron was effective in suppressing the β-grain growth, where the effectiveness depended on the content of boron. An increase in the boron content extended the effective temperature range for β-grain growth suppression. The TiB precipitates were rod-shaped elongated along the forging direction in the β matrix or small round-shaped.
KW - Grain growth
KW - Rare earth oxide
KW - TiB
KW - α-β-type titanium (TO alloy
KW - β-processing
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M3 - Conference contribution
AN - SCOPUS:84883058685
SN - 9787030338945
T3 - Ti 2011 - Proceedings of the 12th World Conference on Titanium
SP - 2077
EP - 2080
BT - Ti 2011 - Proceedings of the 12th World Conference on Titanium
T2 - 12th World Conference on Titanium, Ti 2011
Y2 - 19 June 2011 through 24 June 2011
ER -