Correlation between microstructure and tensile properties of powder metallurgy Ti-6Nb-x(Fe or Mn) alloys

• Published in: Journal of alloys and compounds 2022-12, Vol.926, p.166805, Article 166805
• Main Authors: Manogar, B., Yang, F., Bolzoni, L.
• Format: Article
• Language: English
• Subjects: Alloying elements; Blending elemental; Chemical composition; Eutectoids; Ferrous alloys; Homogeneous microstructure; Iron; Lamellar structure; Manganese; Mechanical properties; Metallurgical analysis; Microstructure; Niobium; Powder metallurgy; Press and sinter; Production costs; Tensile properties; Titanium alloys; Titanium base alloys; Ultimate tensile strength; Yield stress
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.166805

The individual addition of Nb, Fe, or Mn to Ti has been greatly studied, but their combined addition has been much less understood, especially for the Ti-Nb-Mn system. Moreover, the full potential of using powder metallurgy to reduce their manufacturing cost has not been properly exploited and, even though proposed for structural applications, rarely tensile properties were reported. In this study new powder metallurgy Ti‐6Nb‐x(Fe or Mn) alloys were produced and the correlation between their microstructure and tensile properties established. It was found that, for a similar addition of Nb, Mn is a stronger eutectoid β stabiliser compared to Fe leading to more refined lamellar structures and a greater amount of stabilised β phase. Accordingly, higher tensile properties (832–1050 MPa yield stress and 910–1080 MPa ultimate tensile strength) and lower ductility (6.3–1.7 %) were, thus, obtained in ternary Ti-Nb-Mn alloys compared to Ti-Nb-Fe alloys, but the actual stress/strain pairs and hardness are the compromise between the volumetric fraction of residual porosity (3.6–4.9 %), which increases with the amount of alloying elements, and the microstructural changes induced by actual chemical composition. •New powder metallurgy Ti-6Nb-x(Fe or Mn) alloys were produced.•For a similar addition of Nb, Mn is a stronger eutectoid β stabiliser compared to Fe.•Strength and hardness increase with the increment of the amount of alloying elements.