Subscribe to our newsletter to receive the latest news and events from TWI:

Subscribe >
Skip to content

A Review of Post-Build Heat Treatments of Ti-6Al-4V PBF Material

Back to Research Reports 34250-2022-thermoplastic-materials-compatibility-for-hydrogen-service 32221-2020-hybrid-composite-to-metal-joining 32893-2020-mechanical-fastener-coatings-for-corrosion-protection 33557-2020-extreme-high-speed-laser-application-ehla-coatings 33557-2020-extreme-high-speed-laser-application-ehla-coatings 33557-2020-extreme-high-speed-laser-application-ehla-coatings 33557-2020-review-of-electric-vehicle-battery-joining-methods-and-testing A Review of High Power, In-Vacuum and Narrow Gap Laser Welding Processes for Thick Section Welding A Review of High Productivity Additive Manufacture Using a Hybrid Laser-Arc Deposition (HLAD) Process A Review of Micro Welding with Fibre and Disc Continuous-Wave Laser Sources A Review of Residual Stress Measurement Techniques Used for Components Produced Using the Selective Laser Melting Process A Review of the Machine GTAW Ambient Temperature Temper Bead Repair Technique for Nuclear Power Plant Components A Review of Weld Repairs of Mar-M247 and Similar Alloys Applications, Modelling and Manufacturing Processes for Perforated Composites - Literature Review Butt Fusion Welding Procedures and Test Methods Used for PE Pipes Duplex Stainless Steel Welding – A Review of Current Practices Elastic Follow-Up in the Context of Fracture Assessment Flaw Sizing Techniques Using Guided Waves Flaw Sizing Techniques Using Guided Waves Flaw Sizing Techniques Using Guided Waves In-Bore Multi-Positional Laser Welding In-Process Monitoring of Arc Welding for Quality and Defect Detection Mechanical Fastening Technologies for Steel to Aluminium Joining in Automotive Manufacture Process Capability Study for Friction Stir Spot Welding (FSSW) Resistance Spot Welding with Transition Discs – A Review of Dissimilar Joining Using Transition Materials with Specific Reference to Resistance Spot Welding Review of Process Simulations for Metal Additive Manufacturing Surface Modification and Micro-Machining with Pulsed-Laser Sources Wire Fed Electron Beam Additive Manufacture – A State-of-the-Art Review
 

A Review of Post-Build Heat Treatments of Ti-6Al-4V PBF Material

 

By K Georgilas

Background

Ti-6Al-4V (Ti64) is an alpha-beta alloy possessing a high strength-to-weight ratio and excellent corrosion resistance. Ti64 is both solution strengthened as well as precipitation strengthened. The mechanical properties largely depend on the crystal microstructure which can be manipulated through heat treatment. Due to the extensive use of Ti64 in industry, several ‘traditional’ heat treatments exist. The way L-PBF manufacturing process takes place, microstructure, and thus material properties, differs from ‘traditionally’ manufactured components. During the PBF process several defects, including porosity and lack of fusion, can arise. Similarly, microstructure in PBF material is anisotropic, differing between the vertical and horizontal directions, leading to varying mechanical properties in different loading directions. However, heat treatments currently in use by industry have originally been developed with a completely different starting point in terms of material microstructure e.g. cast material. Hence, their applicability and repeatability when performed on AM material is uncertain.

 

The objectives of this report are to describe the metallurgy of Ti64 and the necessity of post thermal treatment to achieve final properties. Review the current state-of-the-art in terms of microstructure and mechanical properties after treatment of the L-PBF Ti64 material. Identify gaps and opportunities in the post thermal treatment of L-PBF Ti64 material.

 

Key Findings

  • ·         Heat treating L-PBF Ti-6Al-4V material is necessary to improve the mechanical properties of the material due to the extensive presence of martensite in the as-built condition.
  • ·         Low temperature heat treatments (<900°C) indicate that martensite is decreased, but not completely dissolved.
  • ·         Higher temperature treatment in the sub transus region (900-1000°C) shows that the presence of martensite in the microstructure is possible.
  • Martensite has been shown to completely dissolve when processed above the β transus (>1000°C) with clear evidence of grain growth.

For more information please email:


contactus@twi.co.uk