3D reconstruction of prior β grains in friction stir-processed Ti-6Al-4V.

The prior β grain structure and orientations in the central stir zone of friction stir-processed Ti-6Al-4V were reconstructed from measured α phase orientations obtained by three-dimensional serial sectioning in a dual-beam focused ion beam scanning electron microscope. The data were processed to obtain the α colony and β grain size distributions in the volume. Several β grains were individually analysed to determine the total number of unique α variants and the respective volume fractions of each.

Using cross-correlation for automated stitching of two-dimensional multi-tile electron backscatter diffraction data.

A method for automatically aligning consecutive data sets of large, two-dimensional multi-tile electron backscatter diffraction (EBSD) scans with high accuracy was developed. The method involved first locating grain and phase boundaries within search regions containing overlapping data in adjacent scan tiles, and subsequently using cross-correlation algorithms to determine the relative position of the individual scan tiles which maximizes the fraction of overlapping boundaries. Savitzky-Golay filtering in two dimensions was used to estimate the background, which was then subtracted from the cross-correlation to enhance the peak signal in samples with a high density of interfaces.

A novel method for acquiring large-scale automated scanning electron microscope data.

Recent software and hardware advances in the field of electron backscatter diffraction have led to an increase in the rate of data acquisition. Combining automated stage movements with conventional beam control have allowed researchers to collect data from significantly larger areas of samples than was previously possible. This paper describes a LabVIEW™ and AutoIT(©) code which allows for increased flexibility compared to commercially available software.

AnyStitch: a tool for combining electron backscatter diffraction data sets.

Recent advances in electron backscatter diffraction equipment and software have permitted increased data acquisition rates on the order of hundreds of points per second with additional increases in the foreseeable future likely. This increase in speed allows users to collect data from statistically significant areas of samples by combining beam-control scans and automated stage movements. To facilitate data analysis, however, the individual tiles must be combined, or stitched, into a single data set.

Novel automatic electrochemical-mechanical polishing (ECMP) of metals for scanning electron microscopy.

A low-stress automated polishing device was developed for preparing titanium and nickel alloys for scanning electron microscopy imaging. The system used pulsed electrochemical reactions within an alkaline electrolyte to generate a thin passivation layer on the surface of the sample, which was removed by the mechanical vibration of the system. The passivation layer development and removal were documented for Ti-6Al-4V and IN718 samples subjected to varying electrical potential cycles and polishing times.