A uniaxial tensile stage with tracking capabilities for micro X-ray diffraction applications

First results are presented for a uniaxial tensile stage designed to operate on a scanning micro X-ray diffraction synchrotron beamline. The new tensile stage allows experiments at typical loading cycles used in standard engineering stress-strain tests. Several key features have been implemented to support in situ loading experiments at the intragranular length scale. The physical size and weight of the load cell were minimized to maintain the correct working distance for the X-ray focusing optics and to avoid overloading the high-resolution raster scan translation stages. A high-magnification optical microscope and image correlation code were implemented to enable automated online tracking capabilities during macroscopic elongation of the sample. Preliminary in situ tensile loading experiments conducted on beamline 12.3.2 at the Advanced Light Source using a polycrystalline commercial-purity Ti test piece showed that the elastic-plastic response of individual grains could be measured with submicrometre spatial resolution. The experiments highlight the unique instrumentation capabilities of the tensile stage for direct measurement of deviatoric strain and observation of dislocation patterning on an intragranular length scale as a function of applied load.