From Closed Packed Metal Structures to Monoclinic SMA and Multiphase Complex Materials: 20 Years of Rietveld Stress-Texture Analyses

Until 20 years ago the only available method for texture analysis was to collect pole figures and residual stress measurement were done using the traditional sin<SUP>2</SUP>(psi) on single peaks. These methodologies could be applied only to single phase materials with high symmetries. In 1992 the Rietveld method was developed also for texture and residual stresses by measuring several full patterns for a significant number of sample tilting and analyze them including a model for the texture and residual stress effects. Several different models were developed over the years and the method has been used for different scientific problems. The procedure was successfully applied to geological, cultural heritage and material science problems using neutron diffraction in bulk samples or X-ray on thin films and in transmission. Now, complex multiphase materials can be analyzed routinely even if triclinic and monoclinic compounds are present like in the case of NiTi SMA alloys.