Light Microscopy

Voort, George F. Vander

doi:10.31399/asm.hb.v09.a0003754

Cited by 3 publications

(1 citation statement)

References 14 publications

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“…(Dark‐field image mode of in (D), captured after 10× indentation suggests that the impression connected by two pores indicated with red arrows is not a macroscopic crack. In the dark‐field mode of optical microscopy, macroscopic cracks and surface pores would appear as bright spots 58 …”

Section: Discussionmentioning

confidence: 99%

Near‐surface plastic deformation in polycrystalline SrTiO₃ via room‐temperature cyclic Brinell indentation

Okafor,

Ding,

Preuß

et al. 2024

J Am Ceram Soc.

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Dislocations are being used to tune versatile mechanical and functional properties in oxides with most current studies focusing on single crystals. For potentially wider applications, polycrystalline ceramics are of concern, provided that dislocations can be successfully introduced. However, in addition to preexisting pores and flaws, a major barrier for bulk plastic deformation of polycrystalline ceramics lies in the grain boundaries (GBs), which can lead to dislocation pile‐up and cracking at the GBs due to the lack of sufficient independent slip systems in ceramics at room temperature. Here, we use the cyclic Brinell indentation method to circumvent the bulk deformation and focus on near‐surface regions to investigate the plastic deformation of polycrystalline SrTiO3 at room temperature. Dislocation etch‐pit analysis suggests that plastic deformation can be initiated within the grains, at the GBs, and from the GB triple junction pores. The deformability of the individual grains is found to be dependent on the number of cycles, as also independently evidenced on single‐crystal SrTiO3 with representative surface orientations (001), (011), and (111). We also identify a grain‐size‐dependent plastic deformation.

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Section: Discussionmentioning

confidence: 99%

Near‐surface plastic deformation in polycrystalline SrTiO₃ via room‐temperature cyclic Brinell indentation

Okafor,

Ding,

Preuß

et al. 2024

J Am Ceram Soc.

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Color Metallography and Electron Microscopy Techniques Applied to the Characterization of 413.0 Aluminum Alloys

Voort¹,

Lozano

Suárez-Peña

2013

Microsc Microanal

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The influence on alloy 413.0 of the refinement and modification of its microstructure was analyzed by means of several microscopy techniques, as well as the effect of the application of high pressure during solidification. For each treatment and solidification pressure condition employed, the most suitable microscopy techniques for identifying and characterizing the phases present were investigated. Color metallography and electron microscopy techniques were applied to the qualitative microstructural analysis. Volume fraction and grain size of the primary α-Al were characterized by quantitative metallographic techniques. The results show that the effect caused by applying high pressure during solidification of the alloy is more pronounced than that caused by modification and refinement of the microstructure when it solidifies at atmospheric pressure. Furthermore, it has been shown that, for Al-Si alloy characterization, when aiming to characterize the primary α-Al phase, optical color metallography observed under crossed polarized light plus a sensitive tint filter is the most suitable technique. When the goal is to characterize the eutectic Si, the use of optical color metallography or electron microscopy is equally valid. The characterization of iron-rich intermetallic compounds should preferably be performed by means of backscattered electron imaging.

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Metallographic Assessment of Al-12Si High-Pressure Die Casting Escalator Steps

Voort¹,

Suárez-Peña²,

Lozano³

2014

Microsc Microanal

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A microstructural characterization study was performed on high-pressure die cast specimens extracted from escalator steps manufactured from an Al-12 wt.% Si alloy designed for structural applications. Black and white, color light optical imaging and scanning electron microscopy techniques were used to conduct the microstructural analysis. Most regions in the samples studied contained globular-rosette primary α-Al grains surrounded by an Al-Si eutectic aggregate, while primary dendritic α-Al grains were present in the surface layer. This dendritic microstructure was observed in the regions where the melt did not impinge directly on the die surface during cavity filling. Consequently, microstructures in the surface layer were nonuniform. Utilizing physical metallurgy principles, these results were analyzed in terms of the applied pressure and filling velocity during high-pressure die casting. The effects of these parameters on solidification at different locations of the casting are discussed.

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Light Microscopy

Cited by 3 publications

References 14 publications

Near‐surface plastic deformation in polycrystalline SrTiO₃ via room‐temperature cyclic Brinell indentation

Near‐surface plastic deformation in polycrystalline SrTiO₃ via room‐temperature cyclic Brinell indentation

Color Metallography and Electron Microscopy Techniques Applied to the Characterization of 413.0 Aluminum Alloys

Metallographic Assessment of Al-12Si High-Pressure Die Casting Escalator Steps

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Light Microscopy

Cited by 3 publications

References 14 publications

Near‐surface plastic deformation in polycrystalline SrTiO3 via room‐temperature cyclic Brinell indentation

Near‐surface plastic deformation in polycrystalline SrTiO3 via room‐temperature cyclic Brinell indentation

Color Metallography and Electron Microscopy Techniques Applied to the Characterization of 413.0 Aluminum Alloys

Metallographic Assessment of Al-12Si High-Pressure Die Casting Escalator Steps

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Near‐surface plastic deformation in polycrystalline SrTiO₃ via room‐temperature cyclic Brinell indentation

Near‐surface plastic deformation in polycrystalline SrTiO₃ via room‐temperature cyclic Brinell indentation