Abstract
This work presents an enhanced instrumented Vickers indentation technique capable of recording force, displacement and acoustic emission (AE) during loading condition. Four materials were chosen for examination; copper, aluminium, steel and as-sprayed HVOF WC-12%Co coating. Results indicate that force-displacement (P-h) profiles are essentially bilinear with two characteristic slopes separated by a distinct displacement arrest for all loads above 98 N. The P-h curve indicates three distinct loading stages (I, II and III) and the stage III mechanical energy increases with loads. About 66% of the hardened steel indentations but only about 18% of the as-sprayed HVOF WC-12%Co coating indentations exhibited an AE record that could be separated into three distinct zones (A, B and C). Where zoning was possible the AE corresponding to a zone correlated well with the AE associated with a loading stage. It is concluded that plastic deformation in soft metals produced little AE, whereas brittle fracture in hardened steel and as-sprayed HVOF WC-12%Co coating produced significant AE. AE may or may not be focused onto particular stages of the indentation and a full measure of crack prevalence would require fractal dimension analysis, which is time consuming, offering a motivation for AE-based indentation testing. © 2011 IOP Publishing Ltd.
Original language | English |
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Article number | 015703 |
Pages (from-to) | - |
Number of pages | 18 |
Journal | Measurement Science and Technology |
Volume | 22 |
Issue number | 1 |
DOIs | |
Publication status | Published - Jan 2011 |
Keywords
- Acoustic emission
- Deformation
- Displacement
- Force
- Fracture
- Hardness
- Indentation
- Instrumented
- Open-loop
- Vickers