A comparative study of deformation structures in primary equiaxed gamma-grains and gamma laths of a creep deformed TiAl-Based alloy

作者：Chen Shanhua^*; Schumacher G

来源：Rare Metal Materials and Engineering, 2007, 36(3): 454-458.

• titanium aluminides
• duplex structure
• transmission electron microscopy
• dislocations
• twins

The microstructure of a Ti-47Al-2Nb-2at%Mn+0.8vol%TiB2 alloy with duplex structure consisting of primary equiaxed gamma-grains and lamellar alpha(2)+gamma colonies after creep deformation at elevated temperatures (650 degrees C similar to 750 degrees C) under 250 MPa similar to 350 MPa was studied by transmission electron microscopy (TEM). In both primary gamma-grains and gamma-laths within lamellar alpha(2)+gamma colonies, the ordinary 1/2 < 110] dislocations and the true twins created by16 < 112] partial dislocations or pseudotwins created by 1/6 < 121] partial dislocations were observed, while planar stacking faults and < 101] superdislocations were more common in y-laths. A detailed contrast analysis by TEM showed that the planar stacking faults lying on {111} planes are bound by all the f.c.c. variants of the 1/6 < 121 > Shockley partial dislocations in contrast to earlier results on stoichiometric binary TiAl. alloys. The observed deformation substructure was compared and contrasted with that of binary TiAl alloys.

• 出版日期2007-3
• 单位成都理工大学