A review article on developing and enhancing the plasticity of ceramic materials at room temperature-summarizing strategies to overcome catastrophic ceramic failure, objectively assessing the challenges in engineering applications, and future innovations in processing and design directions. This article provides a concise distillation of the review to facilitate learning for relevant practitioners.
I. Why Do Ceramics Lack Plasticity?
Metallic materials rely on internal crystal dislocations (lattice slip), allowing atomic layers to gradually move along these channels. The result is commonly observed deformation rather than direct fracture and collapse. The vast majority of ceramic materials are bonded by ionic or covalent bonds, which are strong and stable, making it difficult to generate the slip similar to that in metals. Consequently, the energy required to drive dislocation motion often exceeds the fracture strength the material can withstand, leading to cracking and fragmentation rather than deformation-hence ceramics are often labeled as "brittle."
II. What Can "Plastic" Ceramics Do?
The combination of "impact resistance" with ceramics' inherent high-temperature tolerance and high strength results in aerospace applications such as engines and thermal protection components that are better able to withstand failure risks, significantly enhancing reliability. Enhanced "toughness" also reduces the processing difficulty in advanced semiconductor manufacturing and improves the reliability of precision components in equipment. In short, the high cost and low efficiency and yield associated with precision machining of complex structures in traditional industries can be greatly reduced.
III. Strategies to Overcome Ceramic "Brittleness"
01 Defect Engineering
This approach creates conditions favorable for dislocation motion by controlling crystal defects-such as dislocations, vacancies, grain boundary structures, and local lattice distortions-to lower the threshold for plastic deformation.
For example, a research result published in the January 2025 issue of Materials Today, titled "Harvesting room-temperature plasticity in ceramics by mechanically seeded dislocations," demonstrates that pre-introducing a large number of dislocations can help ceramics initiate plastic deformation at room temperature. After mechanically seeding dislocations, these dislocations can further multiply and move, enabling ceramics to achieve greater compressive plastic strain. Related studies have even achieved plastic compressive strain exceeding 30%.
02 Structural Design
This strategy seeks breakthroughs from the perspective of ceramic structural design, with specific approaches including:
Reducing grain size so that numerous grain boundaries can hinder crack propagation while also providing new deformation mechanisms;
Bio-inspired designs, such as structures resembling nacre, which cause cracks to continuously deflect during propagation, enhancing damage resistance;
Some ceramic materials can achieve plastic deformation through relative grain sliding rather than relying entirely on dislocations;
Introducing amorphous regions to improve local structural adjustability, allowing the material to release stress more readily.
03 Digital Simulation
The AI era has brought benefits to material discovery and experimental testing. Researchers can combine molecular dynamics, first-principles calculations, and materials databases for prediction. This includes correlating characteristic parameters such as Poisson's ratio, Pugh's ratio (i.e., the shear modulus G to bulk modulus K ratio), crystal structure, melting point, and chemical bonding with room-temperature plasticity, thereby enabling efficient and targeted material design.