Etching Method to Create Random Speckle Pattern on Semi-Solid Cast A356 Aluminium for DIC in-situ strain measurement

• Autorzy: Sergolle M. , Santos J. , Kasvayee K. A. , Jarfors A. E. W.
• Języki publikacji: EN

Abstrakty

EN

Aluminum semi-solid casting is constantly evolving, as it offers a combination of reduced shrinkage porosity and gas entrapment defects together with high productivity and an extended die-life. The relationship between the microstructure and stress-strain behavior is not well-understood due to its non-conventional microstructure. In-situ tensile testing, combined with optical microscope and Digital Image Correlation (DIC), has been used for local strain distribution measuements in cast irons. The critical capability was an etching technique to generate a micro-scale random speckle pattern with a sufficiently high speckle density to enable the sufficient spatial resolution of displacement and strain. The current paper focuses on the development of a pit etching procedure for the semi-solid cast A356 aluminum alloy to study local strain accommodation on the microstructure during tensile loading. The critical challenge of this procedure was the generation of homogeneously distributed pits on both the primary aluminum and eutectic regions. Therefore, a heated solution used for wet-etch aluminum in microfabrication was modified as well as a process adapted to generate pits with suitable characteristics. In-situ tensile tests were performed attached to an optical microscope to record the microstructure and displacements during loading. DIC software was used for analysis. The procedure was validated through a comparison between the resulting Young´s moduls using standard tensile testing and the DIC process on the speckle pattern generated. A good fit between the two methods for Young´s modulus was found. The spatial resolution obtained was, however, not sufficient to fully resolve the strain gradients in the microstructure, but it did reveal large strain variations in the microstructure.

Słowa kluczowe

EN

random speckle pattern; cast semi-solid aluminum alloy; pit etching; pitting corrosion; digital image correlation; DIC; local strain

• Wydawca: AGH University of Science and Technology Press
• Czasopismo: Journal of Casting & Materials Engineering
• Rocznik: 2017
• Tom: Vol. 1, no. 1
• Strony: 33--38
• Opis fizyczny: Bibliogr. 20 poz., fot., tab., wykr.

Twórcy

autor

Sergolle M.

• Ecole Nationale Supérieure d'Ingénieurs de Caen - ENSICAEN

autor

Santos J.

• Ecole Nationale Supérieure d'Ingénieurs de Caen - ENSICAEN

autor

Kasvayee K. A.

• School of Engineering, Jönköping University

autor

Jarfors A. E. W.

• School of Engineering, Jönköping University

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