PST双相TiAl类单晶室温变形位错特征

DISLOCATION FEATURES IN POLYSYNTHETICALLY TWINNED TiAl CRYSTALS AFTER DEFORMATION AT ROOM TEMPERATURE

利用透射电子显微镜研究了ＰＳＴ双相ＴｉＡｌ类单晶室温变形后的位错特征。发现除微孪晶和１／２＜１１０］单位位错外，＜０１１］超点阵位错和１／２＜１１２］超点阵位错也参与了变形。＜０１１］位错通常发生：［１０１］→１／２［１０１］＋ＡＰＢ＋１／６［２１１］＋ＳＩＳＦ＋１／６［１ ２］的分解，而１／２＜１１２］超点阵位错则通常分解形成由１／６＜１１２］部分位错构成的层错偶极子。１／２＜１１０］单位位错通常是混合型位错。本文讨论了这些特征对材料室温变形的影响。

The dislocation features in polysynthetically twinned (PST) TiAl crystal deformed at room temperature have been investigated by TEM. Large amount of microtwins,1 / 2< 110] ordinary dislocations, < 011] and 1 / 2<112] superlattice dislocations have been found. The <011] dislocations often dissociate according to the following mode:[101]→1 / 2[101] + APB + 1 / 6[211] + SISF+1 / 6[12] The 1 / 2< 112] dislocations often dissociate to form faulted dipoles bounded by 1 / 6< 1 12]partial dislocations. The effects of these features on the deformation of PST TiAl crystal at room temperature have been discussed.