Dispersoid quantification and size distribution in hot and cold processed AA3103

A quantification procedure coupling Field Emission Gun Scanning Electron Microscope (FEGSEM) and image analysis software has been developed to obtain size distributions of secondary phase dispersoids. The procedure is described in detail for aluminium alloys, and each involved parameter is evaluated separately. The first part of the procedure is the acquisition of the micrograph; both microscope and software parameters are important in this stage. The second part is the most critical step, where the micrograph is transformed to a binary image. Here, the choice of the threshold value is of great importance because it corresponds to the maximum loss of information from the original image. The quantification procedure is then presented with considerations and examples of statistical meaning. The quantification method is applied to a series of AA3103 samples taken from different industrial processing steps. The results obtained are consistent with the expected trends and prove the quantification procedure to be valid.