Hall–Petch relationship in two-phase TiAl alloys with fully lamellar microstructures

The dependences of the room temperature tensile properties of two-phase TiAl alloys with fully lamellar microstructures on colony size and the effects of alloying elements on the k value of Hall–Petch relationship were investigated. It is found that the ultimate tensile strength and the yield strength show Hall–Petch dependences on colony size, but the ductility does not obey a Hall–Petch dependence on colony size. The k value of Hall–Petch relationship increases when Ti–47Al (at.%) is alloyed with interstitial elements C or B, but the additions of substitutional elements Cr or Nb don’t lead to its apparent change.