Summary:
UCLA researchers in the Department of Materials Science and Engineering have developed ultra-strong metal nanocomposites with high ductility, thermal stability, and electrical conductivity.
Background:
In many different applications, including those in the aerospace, defense, electronics, energy, and transportation sectors, nanocrystalline metals play a prominent role. However, these high-strength materials often suffer from low work hardening capacity, and poor thermal stability and electrical conductivity. The existing techniques for modifying those fine-grained metals to achieve high performance have a number of drawbacks and limit their practical utilities. For example, alloying is an effective approach to address some of the aforementioned limitations, but often comes with further reduction of electrical conductivity and faces challenges associated with its sustainability. An alternative approach is to utilize nanosized reinforcements, but these reinforcements tend to agglomerate, making the material susceptible to local stress concentration and premature failure. There is a growing need for a novel method that can produce high-strength metals with desirable mechanical, thermal and electrical properties.
Innovation:
Professor Wang and his research team have developed an effective method, called “nanodispersion-in-nanograins” that can produce nanocrystalline metals such as copper and nickel with excellent mechanical properties, thermal stability, and electrical conductivity. It not only improves the strength of nanograins by 35%, but also leads to improved work hardening and tensile ductility. This innovative strategy creates a uniform dispersion of carbon nanoparticles inside the nanocrystalline metal to achieve higher strength, ductility, thermal stability, and electrical conductivity concurrently, eliminating trade-offs among those mutually exclusive properties. Lab tests showed that this as-fabricated copper nanocomposite could achieve a high tensile strength of 1252 MPa, uniform elongation of 13.3%, and high thermal stability (stable up to 0.72 of melting temperature of copper for 1 hour), together with an improved electrical conductivity. Additionally, this strategy has been successfully extended to another metallic systems, including nanocrystalline nickel, showing its potential for engineering future structural and functional materials with high-performance.
Potential Applications:
• Aerospace industry
• Automotive industry
• Defense sector
• Electronics manufacturing (e.g., integrated circuit leadframes)
• Structural and functional applications in general
Advantages:
• High-performance mechanical properties
• High thermal stability
• Improved electrical conductivity
• Generalizable method for different nanocrystalline metallic system
Development to Date:
Invention has been fully reduced to practice and tested in a laboratory setting. Mechanical, electrical, and thermal analysis has been carried out on the resulting nanocomposites.
Related Papers:
Z. Li, Y. Zhang, Z. Zhang, Y.T. Cui, Q. Guo, P. Liu, S. Jin, G. Sha, K. Ding, Z. Li, T. Fan, H.M. Urbassek, Q. Yu, T. Zhu, D. Zhang, Y.M. Wang, "A nanodisperion-in-nanograins strategy for ultrastrong, ductile and stable metal composites", Nature Communications (accepted for publication as of Sept 8, 2022).
https://www.nature.com/articles/s41467-022-33261-5
Reference:
UCLA Case No. 2023-056
Lead Inventors:
Dr. Yinmin Wang; Dr. Zan Li.