Superplastic behaviour of Ti54M and Ti64

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Abstract

Even though TIMETAL-54M (Ti-5Al-4V-0.6Mo-0.4Fe or Ti54M) has been commercially available for over 10 years, further study of its superplastic properties is still required in order to assess its applicability within the aerospace industry as a potential replacement for other commercial titanium alloys such as Ti-6Al-4V (Ti64). Ti54M is expected to obtain superplastic characteristics at a lower temperature than Ti64 due to its lower beta-transus temperature. The superplastic forming (SPF) capability of alloys that can be formed at lower temperatures has always attracted the interest of industry as it reduces the grain growth and alpha-case formation, leading to longer life for costly high temperature resistant forming tools.
In this work, the SPF characteristics of both Ti54M and Ti64 have been examined by conducting tensile tests according to the ASTM E2448 standard within a range of temperatures and strain values at a fixed strain rate of 1x104/s. A high strain rate sensitivity and uniform deformation at high strains are key indicators in selecting the optimum superplastic temperature. This was observed at 815˚C and 925˚C for Ti54M and Ti64 respectively. The tensile samples were water quenched to freeze their respective microstructure evolution following superplastic deformation and SEM images were captured for grain size and volume fraction of alpha-phase analyses. A slightly higher alpha-grain growth rate was observed during superplastic deformation of Ti64. The initial fine-grain microstructure of Ti54M (~1.6 micron) resulted in a final microstructure with an average grain size of ~3.4 micron and optimum the alpha/beta ratio. Both the fine-grained microstructure and increased amount of beta-volume fraction promotes the superplastic behaviour of Ti54M by grain boundary sliding (GBS). Thus superplastic properties were observed for Ti54M at a lower temperature (~100˚C) than for Ti64.
Original languageEnglish
Pages1-6
Number of pages6
Publication statusPublished - 10 Jun 2019
EventThe 14th World Conference on Titanium - Nantes, France
Duration: 10 Jun 201914 Jun 2019

Conference

ConferenceThe 14th World Conference on Titanium
CountryFrance
CityNantes
Period10/06/1914/06/19

Keywords

  • superplastics
  • Ti54M
  • superplastic forming
  • Ti64
  • superplasticity
  • materials
  • aerospace applications

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  • Activities

    • 1 Participation in conference

    The 14th World Conference on Titanium, Nantes, France, June 10-14th 2019

    Paranjayee Mandal (Participant)

    10 Jun 201914 Jun 2019

    Activity: Participating in or organising an event typesParticipation in conference

    Cite this

    Mandal, P., Gomez-Gallegos, A., Gonzalez, D., ElRakayby, H., & Blackwell, P. (2019). Superplastic behaviour of Ti54M and Ti64. 1-6. Paper presented at The 14th World Conference on Titanium, Nantes, France.