INFLUENCE OF CREEP‐FATIGUE INTERACTION ON HIGH TEMPERATURE FATIGUE CRACK GROWTH BEHAVIOR of Ti‐1100

Abstract— A series of crack growth experiments has been preformed on the near alpha titanium alloy, Ti‐1100, to determine the mechanism of the creep‐fatigue interaction. Based on pure creep crack growth results, the increase in the creep‐fatigue crack growth rate is not amenable to separate contributions of creep crack growth and fatigue crack growth. A mechanism has been proposed to account for the increase in creep‐fatigue crack growth rate that is based on the planar slip of titanium alloys which results in the formation of dislocation pileups at the prior beta grain boundaries and leads to intergranular fracture. This mechanism has been validated through crack growth experiments preformed on a Ti‐1100 that has been microstructurally modified through the precipitation of internal slip barriers. These show that the intergranular fracture and increase in crack growth rate are absent. Copyright © 1994, Wiley Blackwell. All rights reserve