title: The Dependence of Isothermal ω Precipitation on the Quenching Rate in a Metastable β-Ti Alloy.
abstract: The precipitation behavior of the α strengthening phase in metastable β-Ti alloys is highly dependent on heat treatment parameters such as quenching rate, heating rate and ageing temperature. In this paper we have investigated the influence of quenching rate on the formation of isothermal ω precipitates that have been regarded as potent nucleant sites for α precipitation. The results show that the β-solutionized alloy contains a β matrix with a layer structured morphology. Regular atomic movement of the (002)β plane along the <002> direction was observed in the alloy. The increase in quenching rate refines the thickness of layers, subsequently influencing the nucleation and growth of isothermal ω precipitates after ageing treatment. The high quenching rate promotes the occurrence of ω precipitation, broadens the stage of ω precipitation and increases the number density of ω precipitates. Since the isothermal ω phase provides a heterogeneous nucleation site for α precipitates, it is inferred that the quenching rate may indirectly influence the mechanical properties of metastable β-Ti alloy.
authors.affiliation: Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Xiao
authors.affiliation: The University of Queensland, Centre for Advanced Materials Processing and Manufacturing (AMPAM), Brisbane QLD 4072, Australia.
authors.forename: Matthew Simon
authors.initials: MS
authors.lastname: Dargusch
authors.affiliation: Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
authors.forename: Chaoli
authors.initials: C
authors.lastname: Ma