Structural and compositional gradients : basic idea, preparation, applications

No abstract availabl

FGM Research Activities in Europe.

The application of functionally graded materials (FGM) principles is widespread in Europe, despite the lack of national or European programs coordinating the efforts of the individual institutions and researchers. In the following article, the status of research in Europe will be outlined by examples of research projects from various application fields. More detailed information on European FGM research is available from the proceedings of the FGM '94 symposium held in October 1994 in Lausanne, Switzerland. The symposium was organized by B. Ilschner through the Materials Department of the Swiss Federal Institute of Technology of Lausanne.</jats:p

Some aspects of anelastic and microplastic creep of pure Al and two Al-alloys

Anelastic creep of pure Al, commercial Al-Cu and a binary Al-Cu alloy has been measured at room temperature by means of a high resolution laser interferometer. The irreversible component of the deformation was also quantified from measurements of the anelastic creep recovery. The dependence of the deformation-time curves on thermal treatment and cold work is analyzed. The mechanisms responsible for the room temperature anelastic creep are discussed. Materials loaded below their elastic limit can present either a pure anelastic behavior (commercial Al-Cu) or additional viscoelastic creep (pure Al, high purity Al-Cu). For commercial Al-Cu, the presence of an irreversible deformation appears to be mainly related to the state of the surface. A viscoelastic after effect has been measured for this alloy after a Cu-electroplating treatment. As a typical result for room temperature creep, the irreversible deformation depends logarithmically on load time

A Study of the Room Temperature Anelastic Creep of Cu-Be

The future nanotechnology requires materials which are dimensionally and elastically stable within the nm-domain. Because of their elastic stability, Cu-Be alloys are often used for the fabrication of elastic force sensors (spring elements). Anelastic and viscous creep limit the precision of such sensors. Therefore we have studied the anelastic and viscoelastic relaxations of Cu-Be using laser heterodyne interferometery. This method allows to measure flexural displacements as small as 0.1 nm. Our measurements revealed that the anelastic creep of Cu-Be is influenced by the microstructure of the bulk sample as well as the surface condition. The observed influence of the surface on the anelastic creep suggests that the surface dislocation density controls the anelastic relaxation