Optimization of the Post-Process Heat Treatment Strategy for a Near-α Titanium Base Alloy Produced by Laser Powder...

Area of Science:

• Materials Science
• Metallurgy
• Additive Manufacturing

Background:

• Titanium alloys are crucial for lightweight applications due to their high strength-to-weight ratio.
• Near-alpha titanium alloys, particularly Ti6242S, are of interest for additive manufacturing via laser powder bed fusion (LPBF).
• LPBF-produced titanium alloys often exhibit non-equilibrium microstructures requiring post-processing optimization.

Purpose of the Study:

• To optimize post-process heat treatments for LPBF-produced Ti6242S.
• To investigate the impact of heat treatments on tensile and creep strength.
• To understand the decomposition of the as-built microstructure and its effect on mechanical properties.

Main Methods:

• LPBF of Ti6242S alloy.
• Conducting various annealing steps to modify the microstructure.
• Evaluating mechanical properties, including ultimate tensile strength and elongation at fracture.
• Analyzing microstructure-property relationships.

Main Results:

• As-built Ti6242S via LPBF showed high ultimate tensile strength (1530 MPa) but low ductility (A5 = 4.3%).
• Heat treatments were found to decompose the non-equilibrium as-built microstructure.
• A specific triplex heat treatment enhanced elongation at fracture to 16.5% while maintaining a high ultimate tensile strength of 1100 MPa.

Conclusions:

• Optimized heat treatments are essential for tailoring mechanical properties of LPBF Ti6242S.
• Precise heat treatments can significantly improve both ductility and strength.
• This research provides a pathway for enhancing Ti6242S performance for demanding applications.