Dislocations of Ti-600 Alloy Crept at 600°C with Two Stresses

Abstract

Microstructure and dislocations were observed for Ti-600 alloy crept at the temperature of 600°C with the stress of 200MPa and 300 MPa. The results indicate that more precipitation phases could be found both in β phases and at phase boundaries for the alloy after creep tests, and the width of the phase boundary become broader obviously. Also more dislocations could be seen at or around the precipitation phases for the alloy crept at 600°Cwith the stress of 200MPa. Dislocation density is rather big in some regions, dislocations aggregate in precipitation phases, phase boundaries and sub-grain boundaries. Some tangled dislocations or regular arranged dislocations could also be found around precipitation phases. Condensed three-dimensional dislocation meshes could be found in the alloy crept for the alloy crept at 600°Cwith two stresses. For the alloy crept at 600°Cwith the stress of 200MPa, faults originated from boundaries of α lamellar could be found in α lamellar. Some of these faults extend to boundaries of α lamellar, and some stop or end off in α lamellar. While for the alloy crept at 600°Cwith the stress of 300MPa, dislocation tend to arrange in dislocation walls, form bamboo-like structure along the direction of α lamellar, which would expand and penetrate the whole grain of elongated dislocation walls, and at last stop at grain boundaries.