Development of low-cost Ti alloys with a balanced strength and ductility with generation of ultra-fine microstructures

Zou, Zhiyi; Dunstan, Matthew K.; McWilliams, Brandon; Robertson, Stuart; Hague, Richard; Simonelli, Marco

Abstract

This study aims to understand the interplay between strength and ductility in metastable β-Ti alloys based on eutectoid and neutral elements. A low-cost ternary Ti-7Cr-4Sn alloy was prepared by furnace cooling from the single β region at the end of the primary processing. Although isothermal ω, a nano-precipitation generally considered to embrittle the material, is present in the obtained ultra-fine microstructure, the material still exhibits a balanced strength and ductility, with a yield stress of 1067 MPa and elongation of about 10 %. The obtained tensile properties surpass traditional primary processed Ti-6Al-4V, and are comparable to a range of expensive commercial high-strength aerospace Ti alloys. Multiple microstructural features, including grain boundary α (αGB), short rod shape primary α (αP), isothermal ω (ωiso) and ω assisted secondary α (αs) are characterised within the room temperature microstructure. Microstructural analysis reveals that strong Cr segregation in the β phase and slight partitioning of Sn between the α and β phase strengthens the β phase while also preserving ductility in the alloy. This results in a microstructure dominated by the ductile α phase and sub-micron α grain boundaries. This study also discusses the evolution of these microstructural features during different stages of cooling from β matrix, substantiating a promising alloy design strategy for affordable high-performance new Ti alloys.

Citation

Zou, Z., Dunstan, M. K., McWilliams, B., Robertson, S., Hague, R., & Simonelli, M. (2025). Development of low-cost Ti alloys with a balanced strength and ductility with generation of ultra-fine microstructures. Journal of Alloys and Compounds, 1030, Article 180786. https://doi.org/10.1016/j.jallcom.2025.180786

• Journal Article Type: Article
• Acceptance Date: May 4, 2025
• Online Publication Date: May 5, 2025
• Publication Date: May 25, 2025
• Deposit Date: Jul 14, 2025
• Publicly Available Date: Jul 14, 2025
• Journal: Journal of Alloys and Compounds
• Print ISSN: 0925-8388
• Electronic ISSN: 1873-4669
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 1030
• Article Number: 180786
• DOI: https://doi.org/10.1016/j.jallcom.2025.180786
• Public URL: https://nottingham-repository.worktribe.com/output/51611341
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0925838825023473