Surface and Subsurface Damage Caused by Bullet Impacts into Sandstone

The shift of armed conflicts to more urbanised environments has increased the risk to cultural heritage sites. Small arms impacts are ubiquitous in these circumstances, yet the effects and mechanisms of damage caused are not well known. A sandstone target was shot under controlled conditions to investigate surface and subsurface damage. A 3D model of the damaged block, created by structure from motion photogrammetry, shows that internal fracturing was at least as extensive as the visible surface fractures. Backscatter electron imaging of the damaged surface shows a shift from intragranular fracturing and grain size reduction at < 5 mm from the impact point to primarily circumgranular fracturing and grain ‘plucking’ at 20 mm from the impact point. Internal fracture intensity decreased with distance from the centre of the crater. Volumes around the impact point are therefore at greater risk of subsequent weathering deterioration, but significant damage extends to the periphery of the target, rendering whole blocks vulnerable. The surface crater, despite being one of the most conspicuous aspects of conflict damage, has many times less area than internal and surface fractures.

Analysis of Chemical Changes and Microstructure Characterization during Deformation in Ferritic Stainless Steel

Uni- and biaxial tension deformation tests, with different degrees of deformation, have been done on AISI 430 (EN 1.4016) ferritic stainless steel samples, which had both different chemical compositions and had undergone different annealing treatments. The initial and deformed materials were characterized by using electron backscatter diffraction and backscatter electron imaging in a scanning electron microscope together with electron probe microanalysis. The correlation observed among the chemical compositions, annealing treatment, and strain level obtained after deformation is discussed.

Etching and High-Resolution Backscatter Electron Imaging for Semi-Automated Segmentation and Stereology of the Gamma Prime Phase in Ni-based Superalloys

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

The Preparation of Porous Materials Using Liquid Metal Impregnation for BSE Characterization with a Scanning Electron Microscope

The infiltration of porous and particulate materials for metallographic examination with low-melting alloys was first described by Rose and DeRoos . The use of Wood's metal to fill porosity in sandstone was reported by Craze , by Dullien , and by Yadev et al. . Changes in pore structure and phase dispersions in iron ore pellets after simulated blast furnace reduction were reported by Shultz et al. , wherein liquid Bi-Sn impregnation was used to prepare cross sections of deformed and reduced pellets for backscatter electron imaging. Steele and Engel also applied the technique to examine the microstructure in commercial boron nitride (BN). In that study porosity formed by leaching the B2O3phase was filled with liquid metal to allow argon-ion etching to expose the BN microstructure. The characterization of cracks and porosity in cement-based materials after filling with Wood's metal has been reported by Nemati et al. . Cracks developed during compression testing of marble were studied byin-situmetal impregnation in Chang et al. .

Characterization of Closed-Cell Foam Skin Thickness by Backscatter Electron Imaging in an SEM

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008