Effects of Ga, Sn Addition and Microstructure on Oxidation Behavior of Near-α Ti Alloy

Abstract

We investigated the effects of adding Ga or Sn, with almost the same Al equivalent, on the oxidation behaviors of near-α Ti alloy with the bimodal structure and lamellar structure. The replacement of Sn with Ga decreased the alloy weight gain during oxidation, suppressed oxide growth, and improved adherence between the oxide and substrate. A lamellar alloy structure showed a lower weight gain during oxidation compared to the bimodal structure. Unlike conventional near-α alloys, recrystallization occurred near the oxide/substrate interface in Ga-modified alloy, which may contribute to the release of stress, improvement of the adherence between the oxide and substrate, and prevention of oxide-scale spallation from the Ga-modified alloy. A possible mechanism for the recrystallization in the Ga-modified alloy was also discussed.