Investigations on interfaces in metal materials: Cu/Al layered film and intermetallic TiAl alloy as examples

David Wang Auditorium, 3rd floor Dalia Maydan Bldg.
Prof. Limei Cha

Prof. Limei Cha
College of Materials Science and Engineering
Hunan University, China
Interface microstructure is one of the most critical factors to materials properties. To characterize interface structure in nanoscale, transmission electron microscopy (TEM) is a powerful method. Taking a Cu/Al layered film and an intermetallic TiAl alloy as examples, studies on interface and related properties will be discussed in this talk. In the Cu/Al layered film, a new phase with hexagonal close packed (HCP) structure was detected at the Cu/Al interface. Using various kinds of TEM techniques and simulation methods, the atomic structure, chemical composition, thermal stability and the formation mechanism of the new intermetallic phase can be well understood. In TiAl alloys, the softer phase displays surprisingly a higher hardness. Employing TEM to analyze the interface structure in nanoscale, it was found that a size effect contributes to this mechanical behavior. A simple model was used to describe the interplay of the phase volume fraction and the lamellae width on hardness. In addition, some phenomena appearing at the Fe/TiB2 interface would be presented briefly.