Instrumentation Development for Crack Detection of Surface and Subsurface Defects in Green-State P/M Compacts Through Multiprobe Electric Resistivity Testing
Over the past two years an electrostatic instrumentation approach has been pursued whereby direct current is injected into green-state powder metallurgy (P/M) compacts followed by subsequent recording of the voltages on the surface. Owing to the fact that P/M specimens are moderate to low conducting samples, even small currents can produce a significant voltage distribution across the surface that can be recorded by an array of sensing probes arranged in a planar or non-planar configuration [1–4]. The presence of flaws, manifesting themselves in conductivity contrasts, can be sensed as a different voltage distribution when compared to the unflawed baseline voltage response.
KeywordsFlaw Type Voltage Distribution Subsurface Flaw Flawed Sample Hairline Crack
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