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Using a Bridgman vertical vacuum furnace,Ti-45Al-8Nb-(W,B,Y) (at.%) bars,which were prepared from a plasma arc melting (PAM) ingot,were directionally solidified at growth rates of 10,15,and 20 μm/s.Polysynthetic twinned (PST) crystal with an aligned lamellar microstructure was obtained at the growth rate of 15 μm/s because of high Nb addition.The principle of PST crystal growth and the effect of Nb element were discussed.The results of investigations on microstructure and micromechanical properties of the directionally solidified (DS) bars of Ti-45Al-8Nb-(W,B,Y) alloy are briefly summarized.
Using a Bridgman vertical vacuum furnace, Ti-45Al-8Nb- (W, B, Y) (at.%) Bars, which were prepared from a plasma arc melting (PAM) ingot, were directionally solidified at growth rates of 10,15 , and 20 μm / s. Polysynthetic twinned (PST) crystal with an aligned lamellar microstructure was obtained at the growth rate of 15 μm / s because of high Nb addition. The principle of PST crystal growth and the effect of Nb element were discussed. The results of investigations on microstructure and micromechanical properties of the directionally solidified (DS) bars of Ti-45Al-8Nb- (W, B, Y) alloy are briefly summarized.