Hot Deformation Behavior and Workability of In Situ TiB2/7050Al Composites Fabricated by Powder Metallurgy

Area of Science:

• Materials Science
• Metallurgy
• Composite Materials

Background:

• Powder metallurgy is a key technique for fabricating advanced composite materials.
• Understanding the high-temperature deformation behavior of metal matrix composites is crucial for optimizing manufacturing processes.

Purpose of the Study:

• To investigate the hot workability of in situ TiB2/7050Al composites.
• To establish the constitutive equation and hot processing map for these composites.
• To elucidate the underlying deformation mechanisms during isothermal compression.

Main Methods:

• Isothermal compression tests were conducted on in situ TiB2/7050Al composites.
• Testing parameters included temperatures from 300-460 °C and strain rates from 0.001 s⁻¹ to 1 s⁻¹.
• Analysis involved establishing the Arrhenius constitutive equation and constructing a hot processing map.

Main Results:

• The composites demonstrated excellent hot workability, characterized by low activation energies and broad processing windows.
• Discontinuous/continuous dynamic recrystallization (DDRX/CDRX) and grain boundary sliding (GBS) were identified as dominant deformation mechanisms.
• Uniform TiB2 particles and fine grain structures promoted DDRX at high Zener-Hollomon parameter (Z) values, while GBS dominated at low Z values.

Conclusions:

• The established hot processing map provides optimal processing windows for TiB2/7050Al composites.
• The interplay between DDRX, CDRX, and GBS, influenced by Z values, dictates the material's workability.
• Stable fine grain structures, maintained by nanoparticle pinning, facilitate GBS and ensure good workability at lower Z values.