DEVELOPMENT OF B2-TYPE INTERMETALLIC COMPOUND ALLOYS WITH ANOMALOUS TEMPERATURE DEPENDENCE OF STRENGTH FOR RESISTANCE TO CREEP.

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The Burgers vector and the morphological feature of the dislocation in B2-type CoTi single crystals were investigated by means of high-resolution transmission electron microscopy. The following results were obtained.At intermediate temperature, the screw component of the dislocations with <001> type Burgers vector was dominant and dissociated with unstable stacking fault on (010) plain. this dissociation of screw dislocation may affect the mechanical properties of B2-type intermetallic compound CoTi.And also, the mechanical behaviors, the Burgers vectors, the activated slip plains and the morphological feature of dislocation in B2-type CoZr and CoHf polycrystals were investigated by means of compression test machine and transmission electron microscopy at a wide range of temperatures.In both CoZr and CoHf, it was observed the yield strength anomaly at intermediate temperatures, and Burgers vectors were the <001> type and associated slip plain were {110} as similar to that of CoTi single crystals.