Different origins of grain size and composition effects on creep in TiAl

✍ Scribed by K Maruyama; T Takahashi; H Oikawa

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 423 KB
• Volume: 153
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(92)90233-q

✦ Synopsis

Grain size and aluminum content strongly affect creep rate of single phase ~,-TiA1. Origins of the grain size and composition dependence have been discussed based on creep curve analysis by the theta concept. The deformation of TiAI occurs by dislocation creep and the rate constant of creep deformation itself is independent of grain size. With decreasing grain size, strain hardening becomes less significant, while weakening becomes more significant. These microstructural effects apparently cause the large grain size dependence of the creep rate. Deviation from the stoichiometry raises diffusivity, and results in the high rate constant and the associated high creep rate of off-stoichiometry TiM. Less strain hardening and greater weakening in off-stoichiometry TiAI also contribute to the composition dependence of the creep rate.