TEM characterization of the fine scale microstructure of a Roman ferrous nail

Douin, Joël; Henry, Ovri; Dabosi, F.; Sciau, Philippe

doi:10.1051/epjap/2010074

Cited by 2 publications

(4 citation statements)

References 15 publications

(15 reference statements)

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“…8d) reflections, cementite is highly textured. It has been shown that the orientation of cementite crystals can be related to the orientation of neighbouring ferrite grains (Douin et al, 2010). We then attributed the strong texture of the cementite phase to the presence of adjacent ferrite crystals.…”

Section: Roman Nailmentioning

confidence: 77%

“…8c and 8d), which is characteristic of pearlite colonies (a mix of ferrite/ cementite in a nanocrystalline form). The absence of additional phases besides ferrite and cementite in the analysed zones is characteristic of a slow cooling step during the fabrication process (Douin et al, 2010). As shown in Fig.…”

Section: Roman Nailmentioning

confidence: 82%

“…In this study, we analyse the distribution of the different phases from the top surface to the core of the nail, the correlation between these micro/nano phases (distribution, strain), and the influence of the phase distribution on material properties (hardness, elasticity). The investigated sample was previously studied by transmission electron microscopy (Douin et al, 2010). We expected to get complementary and reliable information by investigating a more representative volume.…”

Section: Roman Nailmentioning

confidence: 99%

“…To do so, a mapping of the regions of interest will be performed with a poly-and a monochromatic microbeam to get the required spatial resolution. The three selected samples show a strong heterogeneity over micrometre length scales where the role of interfaces and phase distribution, related to the material properties, needs to be understood and for which data are missing: (i) terra sigillata ceramics from the Roman period (Sciau, Relaix et al, 2006), composed of several parts (slip and body) and several phases with a grain size varying from nanometres to a few micrometres; (ii) flint tools from the Neolithic period (Rıos et al, 2001), where the main quartz phase shows a grain size heterogeneity related to its geological formation; and (iii) iron nails from the Roman period (Douin et al, 2010), composed of several phases and in which the size of the ferrite domains varies depending on their location.…”

Section: Introductionmentioning

confidence: 99%

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Complementary use of monochromatic and white-beam X-ray micro-diffraction for the investigation of ancient materials

et al. 2015

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Archaeological artefacts are often heterogeneous materials where several phases coexist in a wide grain size distribution. Most of the time, retrieving structure information at the micrometre scale is of great importance for these materials. Particularly, the organization of different phases at the micrometre scale is closely related to optical or mechanical properties, manufacturing processes, functionalities in ancient times and long-term conservation. Between classic X-ray powder diffraction with a millimetre beam and transmission electron microscopy, a gap exists and structure and phase information at the micrometre scale are missing. Using a micrometre-size synchrotron X-ray beam, a hybrid approach combining both monochromatic powder micro-diffraction and Laue single-crystal micro-diffraction was deployed to obtain information from nanometre-and micrometre-size phases, respectively. Therefore providing a way to bridge the aforementioned gap, this unique methodology was applied to three different types of ancient materials that all show a strong heterogeneity. In Roman terra sigillata, the specific distribution of nanocrystalline hematite is mainly responsible for the deep-red tone of the slip, while the distribution of micrometre-size quartz in ceramic bodies reflects the change of manufacturing process between pre-sigillata and high-quality sigillata periods. In the second example, we investigated the modifications occurring in Neolithic and geological flints after a heating process. By separating the diffracted signal coming from the nano-and the micrometre scale, we observed a domain size increase for nanocrystalline quartz in geological flints and a relaxation of the residual strain in larger detritic quartz. Finally, through the study of a Roman iron nail, we showed that the carburation process to strengthen the steel was mainly a surface process that formed 10-20 mm size domains of single-crystal ferrite and nanocrystalline cementite.

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Section: Roman Nailmentioning

confidence: 77%

Section: Roman Nailmentioning

confidence: 82%

Section: Roman Nailmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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