IN SITU OBSERVATIONS OF MICROCRACK NUCLEATION IN ODS FERRITIC STEEL
ODS铁素体钢中微裂纹形核过程的TEM原位观察

Dislocations were emitted from a crack tip, and nucleation, blunt and propagation of a microcrack with a nanometre in size are studied through in situ tensile test for thin foil speCimens of ODS ferritic steel by transmission electron microscopy (TEM). The results show that dislocations are emitted from a crack tip and a dislocation free zone (DFZ) forms in front of the crack tip. Under the condition of constant displacement, the microcracks nucleate continuously at the crack tip or discontinuously in the DFZ, and they are not blunted into voids.