Residual stress measurement of gold artefacts by Debye ring analysis

摘要

In the case of precious and rare art manufacts, usually bearing complex geometry, the conventional X-ray Diffraction technique can be very difficult or even impossible to be applied. On the contrary by means of microbeam small area can be analysed and the microstructure of differently treated surfaces can be investigated. Recently, two-dimensional (2D) detectors have been developed for laboratory X-ray diffractometers. Thus, nowadays it is possible to collect high quality diffraction data of a significant part of the diffraction cones during the exposure time and the structure and microstructure of small surface area can be assessed. Moreover, by the analysis of the diffraction cones distortion, the residual and/or applied stresses can be measured. In the present work the structure, microstructure, and residual stress present in representative gold artefacts are discussed mainly on the basis of bidimensional X-ray microdiffraction (μXRD~2) and microfluorescence (μXRF). A gold ring has been analysed before and after deformation and the distribution of residual stress measured along the circumference has been compared with the stress analysis results from FEM simulation.