Appraising near surface material integrity using electrochemical jet processing

A Speidel, I Bisterov, J Mitchell-Smith and A T Clare 

The absolute and relative orientations of grains within crystalline materials and the presence of manufacturing defects influence the resulting properties and the subsequent failure modes and design lives of created parts. Information in this regard is therefore invaluable to engineers working to maximise safe operating limits and minimise resource-intensive processes. Techniques yielding information at cost levels and timescales compatible with both contemporary production-line manufacturing processes, as well as scheduled maintenance assessments throughout the service life, remains challenging. This talk reports on electrochemical jet processing (EJP), coupled with accurate topographic acquisition, to rapidly characterise crystallographic texture, grain flow and other microstructural effects in different engineering materials. Implementation of selective EJP allows localised dissolution to be anisotropic and dependent on etch-rate selectivity, defined by the crystallography. Consistent with etching techniques, EJP can therefore generate complex but characteristic topographies within areas of interest in a safe manner. Through rapid surface processing and analysis, textural information can be elucidated and resolved over limited timescales and intervention. In addition, by understanding the process energetics, additional information pertaining to the macroscale stress condition may be resolved in a single-step process.