Microstructure of creep-deformed V–4Cr–4Ti strengthened by precipitation and cold rolling

The microstructural processes were investigated for V–4Cr–4Ti alloys strengthened by precipitation and cold rolling during thermal creep deformation and thermal aging in identical conditions at 1023 K. Cold rolling to precipitate-hardened V–4Cr–4Ti can suppress precipitate coarsening during the following high temperature aging. The dislocations observed were mixture of a〈1 0 0〉 and a/2〈1 1 1〉 types in the specimens with only thermal aging, and predominantly of a/2〈1 1 1〉 type in the specimens after the creep deformation. Coarsening of the precipitates was observed after the creep deformation. It seems to be essential to avoid the recovery of sessile a〈1 0 0〉 type dislocations induced by cold rolling for the purpose of maintaining the high temperature strength.