Significant breakthroughs have been made in the study of atomic diffusion behavior of restricted cry

2024-03-13

Sub diffusion is a common phenomenon in nature, and it is also a basic process to control the structure and properties of materials in the process of material preparation and processing. By utilizing the high atomic diffusion rate of metals, the structure and properties of metal materials can be significantly controlled at lower temperatures, resulting in excellent comprehensive properties. However, high diffusion rates can cause structural instability of metal materials at high temperatures, leading to the loss of many excellent properties. How to effectively reduce atomic diffusion in metals and alloys and improve the stability of material structure and properties at high temperatures is one of the important bottlenecks that restrict the development of high-performance metal materials.

Recently, the National Key R&D Program "Nanotechnology" Key Special Project "Research on the Construction and Service Behavior of New Nanometal Materials" managed by the High tech Research and Development Center of the Ministry of Science and Technology has made significant research progress. The research and development team of the Institute of Metals, Chinese Academy of Sciences, has found through collaborative research that the restricted crystal structure at high temperatures can effectively suppress atomic diffusion in supersaturated aluminum magnesium alloys with extremely fine grains. By forming a stable structure of confined crystals, as the annealing temperature of the sample increases, the metal phase precipitation process controlled by atomic diffusion and the coarsening behavior of grain growth are effectively suppressed to the equilibrium melting temperature range. Near this temperature, the apparent cross-border diffusion rate of the aluminum magnesium alloy sample is reduced by about 7 orders of magnitude compared to the unrestricted crystal structure. Restricted crystals provide a strong barrier to prevent the diffusion of atoms in metals and alternative alloys, achieving much higher stability than traditional alloys at melting temperatures.

This research achievement is expected to develop cutting-edge engineering alloys using restricted crystal structures, and open up a new path for the development of high-performance and high thermal stability metal materials. The relevant research results were published in Science in August 2021.

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