Preparation conditions, such as temperature and pressure, etc., can drastically affect the structure and phase of alloy materials. XRD provides a convenient and nondestructive method for phase identification. Rigaku's SmartLab multipurpose diffractometer is equipped with an automatic 4-inch XY mapping stage with an X,Y resolution better than 0.1 mm. The XY mapping stage can also be used as an automatic sample changer. The figure below presents the XRD results from 15 samples, cut from various positions of a single piece of Al-Cu alloy prepared under gradient stress, measured with the 4-inch XY stage as the sample changer. Each sample is about 1.5 cm. Clearly the distribution of Cu additives is not uniform in this particular alloy.