Liaoning Materials Laboratory discovered "negative interface" in metals, achieving sub-nanometer structural alloy reinforcement.

According to the news from the Department of Science and Technology of Liaoning Province, recently, a joint research team of Liaoning Materials Laboratory and the Institute of Metals Research of the Chinese Academy of Sciences discovered a more stable interface in metals than twin boundaries called "negative interface". In Ni supersaturated solid solution alloys containing Mo, the coherency interface between face-centered cubic and close-packed hexagonal lattices has negative excess energy, lower than the energy of twin boundaries, allowing for extremely high interface density with an average interface thickness of less than 1nm, reaching the limit of interface density in materials. The extremely high density "negative interface" has intrinsic stability, effectively preventing dislocations and interface movement, completely inhibiting material plastic deformation, thereby increasing the material strength close to the theoretical limit. Unlike traditional methods of metal strengthening that typically lead to a decrease in elastic modulus, the "negative interface" significantly increases the material's elastic modulus while improving strength. This "negative interface" strengthening mechanism is applicable to multiple alloy systems. This important discovery marks the entry of structural control of metal materials into sub-nanometer scale, where stable interfaces at the limit scale can change the atomic bonding state of lattices, thereby significantly enhancing performance and opening up a new dimension for the design of next-generation high-performance metal materials.