Seeding ductile nanophase in ceramic grains.

Area of Science:

• Materials Science
• Nanotechnology
• Mechanical Engineering

Background:

• Brittle fracture, specifically transgranular brittle fracture, is a primary failure mechanism in ceramics and ceramic matrix composites.
• Achieving enhanced strength in these materials without compromising toughness presents a significant challenge.

Purpose of the Study:

• To propose and demonstrate an innovative strategy for simultaneous strengthening and toughening of brittle materials.
• To investigate the mechanisms behind introducing and controlling ductile nanoparticles within ceramic grains.
• To validate the approach using cemented tungsten carbides (WC-Co) as a model system.

Main Methods:

• Introduction of specific ductile coherent nanoparticles into ceramic grains.
• Utilizing cemented tungsten carbides (WC-Co) to demonstrate the concept.
• Analysis of nanoparticle formation, quantity, size, and distribution within ceramic grains.
• Evaluation of fracture modes and mechanical properties (strength and strain limit).

Main Results:

• Successfully reduced the fraction of transgranular fractures in the brittle ceramic phase.
• Achieved ultrahigh strength and toughness in WC-Co by seeding metallic nanoparticles within WC grains.
• Demonstrated a significant increase in both strength and strain limit compared to conventional materials.

Conclusions:

• The proposed strategy of introducing ductile coherent in-grain nanoparticles effectively achieves coordinated strengthening and toughening.
• This approach is broadly applicable to various ceramics and ceramic matrix composites.
• Superior comprehensive mechanical properties can be obtained for brittle materials using this method.