Microstructure and tensile properties after thermohydrogen processing of Ti-6 Al-4V

Area of Science:

• Materials Science
• Metallurgy
• Titanium Alloys

Background:

• Thermohydrogen processing (THP) utilizes hydrogen as a temporary alloying element.
• This technique refines microstructure and enhances mechanical properties of titanium alloys.
• THP enables near-net-shape modification, crucial for powder metallurgy and castings without mechanical working.

Purpose of the Study:

• To evaluate two THP methods (THP-A and THP-B) on Ti-6Al-4V.
• To assess microstructural refinement and mechanical property changes.
• To compare the efficacy of THP-A and THP-B for titanium alloy processing.

Main Methods:

• Two THP variants (THP-A and THP-B) applied to Ti-6Al-4V.
• THP-A involves eutectoid decomposition of beta(H) phase.
• THP-B involves isothermal decomposition of alpha('') martensite after quenching hydrogenated samples.
• Microstructural analysis via optical and electron microscopy.
• Tensile testing to evaluate mechanical properties.

Main Results:

• Both THP-A and THP-B refined the coarse, lamellar microstructure of Ti-6Al-4V.
• Both processes increased the alloy's strength compared to the initial material.
• THP-B resulted in a severe reduction in ductility.
• THP-A demonstrated a more balanced improvement in mechanical properties.

Conclusions:

• Thermohydrogen processing is effective in refining Ti-6Al-4V microstructure.
• THP-A offers a promising route for improving strength and ductility.
• THP-B enhances strength but compromises ductility, requiring further optimization for certain applications.