Monash University in Australia launched the world's first research project and found a technology that can be used to make stronger and lighter magnesium alloys, thereby improving the structural integrity of products in the automotive and aerospace industries.
Researchers at Monash University, the Commonwealth Scientific and Industrial Research Organization of Australia (CSIRO) and Chongqing University have discovered the pattern of alloy element segregation in the twin boundary in an environment with low electron voltage and using atomic resolution X-ray images .
Engineers are always looking for strong, lightweight materials for cars, airplanes, and high-speed vehicles to improve fuel efficiency, aerodynamics, speed, and weight load.
The results of this research are significant because in the process of thermo-mechanical processing and application, because light magnesium is easily deformed, magnesium alloys cannot replace steel on a large scale. At the same time, so are other alloys such as aluminum and titanium.
Nie Jianfeng, a professor of the Department of Materials Science and Engineering at Monash University, said: "Light magnesium has great potential for energy saving and environmental protection, but the segregation of such materials is easily damaged by electron beams. When the solute atoms segregate into a single atomic column, it will affect To the formability, deformability and compressive strength of magnesium products. "
"But we proved that at a lower electron acceleration voltage (120 kV) instead of the commonly used 300 kV voltage, it is possible to solve this problem with an X-ray map with atomic resolution. In addition, we further found that the new type of segregation The model has increased the boundary pinning effect by more than 30 times, and the mechanism of twin migration has also changed from a generally accepted model to a new model. "
The researchers used a magnesium alloy composed of neodymium and silver in the study, which has excellent mechanical properties at room temperature and high temperature. The researchers found that when the twin boundaries were filled with neodymium and silver, the elastic strain of the alloy reached its limit, while the shear stress was significantly improved, a 33-fold increase. The charge density between silver and neodymium and magnesium is increased, indicating that the bonding between the twins is enhanced. When an external force is applied, magnesium is pushed towards neodymium, away from silver, thus forming a stronger and lighter alloy.
Nie Jianfeng said: "Our research shows that it is possible to analyze the structure and chemistry of solute segregation with metal alloys (with complex compositions) from an atomic perspective."