Phase equilibria in Ti-rich portion and thermodynamic re-optimization of Co-Ti system  

作　　者：Hua-kou Yang Chen-yang Zhou Hang Wang Bin Yang 

机构地区：[1]Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China [2]Jiangxi Advanced Copper Industry Research Institute,Yingtan 335000,Jiangxi,China

出　　处：《Journal of Iron and Steel Research International》2022年第6期914-924,共11页

基　　金：This work was supported by Scientific Research Starting Foundation for Advanced Talents of Jiangxi University of Science and Technology(Grant No.205200100063)and Open Foundation of Jiangxi Advanced Copper Industry Research Institute.

摘　　要：The experimental and thermodynamic studies of the Co-Ti system are an important part of the project to build a thermodynamic database for multicomponent Co-Ti-based alloys.Several key alloys were prepared and then examined for microstructural,compositional and thermal analyses to determine the Ti-rich phase equilibria.According to the available experimental information,the Co-Ti system was thermodynamically re-optimized on the basis of CALPHAD method.Four disordered solutions,liquid,fcc-A1(α-Co),bcc-A2(β-Ti)and hcp-A3(ε-Co andα-Ti)were modeled as substitutional ones.CoTi_(2)with limited solubility was treated as a stoichiometric compound,whileγ-Co_(2)Ti andβ-Co_(2)Ti with certain solubility were described in the form of(Co,Ti)2(Co,Ti)1 using a two-sublattice model.A single Gibbs energy function was employed to model two order–disorder transformations from fcc-A1 to fcc-L12(Co3Ti)and from bcc-A2 to bcc-B2(CoTi).A group of self-consistent thermodynamic parameters of the Co-Ti system were obtained.With these thermodynamic parameters,the experimental data can be described more reasonably and satisfactorily.

关 键 词：Co-based SUPERALLOY Co-Ti SYSTEM Phase equilibrium CALPHAD method Order–disorder transformation 

分 类 号：TG146.23[一般工业技术—材料科学与工程]