Powder metallurgy processing of Nb-modified near β titanium alloys prepared with elemental powders

ABSTRACT

Near β Ti alloys typically show high specific strength and provide a wide spectrum of mechanical properties with different heat treatments. In this work, a commercial near β Ti alloy Ti-5553 (Ti-5Al-5V-5Mo-3Cr-0.5Fe) was prepared through powder metallurgy using the blended elemental powder approach. Additionally, alloy modifications with 6 wt.% Nb (Ti-6Nb-5Al-2.5V-5Mo-3Cr-0.5Fe) and 12 wt.% Nb (Ti-12Nb-5Al-5Mo-3Cr-0.5Fe) were investigated. Specimens were prepared by uniaxial cold compaction of blended powders at room temperature with sintering conducted at 1300°C for 2 h under Ar atmosphere. Microstructure investigation revealed reasonable homogenisation of alloying elements and colony sizes in the order of 80-100 μm with porosity below 10%. Moreover, the bending strength of as-sintered Ti-12Nb-5Al-5Mo-3Cr-0.5Fe was about 850 MPa and the micro-Vickers hardness was approximately 370 HV. The alloy modifications with Nb increased strength without loss in flexural strain.

KEYWORDS:

• Powder metallurgy
• β titanium alloys
• Ti-5553
• sintering
• mechanical behaviour

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the São Paulo Research Foundation (FAPESP) under Grant 2018/18293-8, and the Brazilian National Council for Scientific and Technological Development (CNPq) under Grant 226462/2013-7.