Alloy design by tailoring phase stability in commercial Ti alloys

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:815

Article

Zhao, G-H^1,7  Liang, X. Z.¹  Xu, X.^2,8,9  Gamza, M. B.³  Mao, H.^4,5  Louzguine-Luzgin, D., V^6,10  Rivera-Diaz-del-Castillo, P. E. J.¹ 

[1] Univ Lancaster, Dept Engn, Lancaster, England

[2] Imperial Coll London, Dept Mat, London, England

[3] Univ Cent Lancashire, Jeremiah Horrocks Inst Math Phys & Astrophys, Preston, Lancs, England

[4] KTH Royal Inst Technol, Dept Mat Sci & Engn, Stockholm, Sweden

[5] Thermocalc Software AB, Stockholm, Sweden

[6] Tohoku Univ, WPI Adv Inst Mat Res, Sendai, Miyagi, Japan

[7] Univ Oxford, Dept Engn Sci, Oxford, England

[8] Sun Yat Sen Univ Shenzhen, Sch Mat, Shenzhen, Peoples R China

[9] Southern Marine Sci & Engn Guangdong Lab Zhuhai, Guangzhou, Peoples R China

[10] Natl Inst Adv Ind Sci & Technol, Math Adv Mat OIL, Tsukuba, Ibaraki, Japan

关键词: Ti alloys;    Physical modelling;    Alloy design;    Phase transformation;    Plasticity;   

DOI  :  10.1016/j.msea.2021.141229

来源: Elsevier

【 摘 要 】

The mechanical characteristics and the operative deformation mechanisms of a metallic alloy can be optimised by explicitly controlling phase stability. Here an integrated thermoelastic and pseudoelastic model is presented to evaluate the beta stability in Ti alloys. The energy landscape of beta ->alpha ' /alpha '' martensitic transformation was expressed in terms of the dilatational and transformational strain energy, the Gibbs free energy change, the external mechanical work as well as the internal frictional resistance. To test the model, new alloys were developed by tailoring two base alloys, Ti-6Al-4V and Ti-6Al-7Nb, with the addition of beta-stabilising element Mo. The alloys exhibited versatile mechanical behaviours with enhanced plasticity. Martensitic nucleation and growth was fundamentally dominated by the competition between elastic strain energy and chemical driving force, where the latter term tends to lower the transformational energy barrier. The model incorporates thermodynamics and micromechanics to quantitatively investigate the threshold energy for operating transformation-induced plasticity and further guides alloy design.

【 授权许可】

Free