Łukasz Ciupiński

Comparative Laser Spectroscopy Diagnostics for Ancient Metallic Artefacts Exposed to Environmental Pollution

Metal artworks are subjected to corrosion and oxidation processes due to reactive agents present in the air, water and in the ground that these objects have been in contact with for hundreds of years. This is the case for archaeological metals that are recovered from excavation sites, as well as artefacts exposed to polluted air. Stabilization of the conservation state of these objects needs precise diagnostics of the accrued surface layers and identification of original, historical materials before further protective treatments, including safe laser cleaning of unwanted layers. This paper presents analyses of the chemical composition and stratigraphy of corrosion products with the use of laser induced breakdown spectroscopy (LIBS) and Raman spectroscopy. The discussion of the results is supported by material studies (SEM-EDS, XRF, ion-analyses). The tests were performed on several samples taken from original objects, including copper roofing from Wilanów Palace in Warsaw and Karol Poznański Palace in ŁódŸ, bronze decorative figures from the Wilanów Palace gardens, and four archaeological examples of old jewellery (different copper alloys). Work has been performed as a part of the MATLAS project in the frames of EEA and Norway Grants (www.matlas.eu) and the results enable the comparison of the methodology and to elaborate the joint diagnostic procedures of the three project partner independent laboratories.

Methods for the characterization of grain size

Modern stereological procedures are applied to the quantification of a grain population in a pure iron sample. These procedures can be efficiently applied to give information on the true three-dimensional size and the spread thereof.

Quantitative description of the morphologic texture in an Al-Li alloy

Abstract The aim of the present paper is to present a method for quantitative description of the morphologic texture of grains in polycrystals. This method is based on computer-aided image analysis. It has been verified for studies of grain shape in commercial Al–Li-based alloy (8090). The results obtained for this alloy show that even small changes in the alignment and elongation of grains can be detected. The quantified information on morphological texture of grains can be further used to measure its contribution to anisotropy of the material in question.

On the Application of Lewis’s Law to Grain Sections of Polycrystalline Metallic Materials

Abstract The aim of the present study was to verify the Lewis law for microstructures of a wide range of metallic polycrystals subjected to various degrees of plastic deformation and heat treatment. The differences in the technological history of the specimens resulted in various grain shapes (quantified in terms of the ratio of d max / d 2 , where d max stands for maximum cell chord and d 2 is the equivalent circle diameter). The cell structures also differed in their mean values of grain-section area, E ( A ), and the diversity/spread in grain-section size [quantified by using the grain-section area coefficient of variation, CV ( A )]. An analysis of the data points has led to the conclusion that the they can be best approximated by two linear relations with different values of Lewis slopes, α. The first approximates the data for grains with a number of edges from 2 to 5 and the second one from 6 upward. It is suggested here that the existence of thee two regions can be rationalized by the distinct geometry/physical properties of the large grains, which are expected to have a number of edges larger than 6.

Carbon fiber composite grade A412N resistance to intense plasma-ion streams emitted from PF-1000

Due to extreme conditions prevailing in the present fusion reactor chambers and for the future fusion reactor chambers the use of modern materials with special properties characterized by resistance to high temperatures, thermal shocks, unique resistance to erosion, high thermal conductivity and lack of interaction with the plasma particles is required. The investigation in this study concerns carbon fiber composites which exhibit several features that make them attractive for use in fusion devices. The paper describes the microstructural and surface changes of the composite induced by high-energy deuterium plasma. The PF-1000 facility was used to produce plasma impinging the composite target. Samples were tested before and after repeated emissions under those conditions.

Hydrogen Influence on Microstructure and Properties of Novel Explosive Welded Corrosion Resistant Clad Materials

The aim of this work was to investigate whether the explosively welded metals are susceptible to hydrogen degradation. The materials described in this article are widely used nickel alloy Inconel C-276 and super duplex steel SAF 2507 as clad materials for their superior resistance to corrosive environment and low alloy steel P355NH as a base material. It was observed that at the explosive bonded interface between the base steel and the stainless steel some local melting zones are formed. It was found that the cathodic hydrogen charging causes changes in the microstructure of bonded materials and decreases the shear strength of bonds as well as the corrosion resistance of clads.

Investigation of tungsten surface changes after interaction with dense plasma streams compared with the results given by a simple 1D model

Abstract In this work, plasma–target interactions on tungsten samples, carried out in a Mather-type plasma focus PF-1000 device, were investigated. The experimental results have been compared to 1D model computer simulations. Samples were studied by means of scanning electron microscopy, focused ion beam microscopy and precise measurements of weight loss. Additionally, simulations based on the numerical solution of a 1D heat conductivity equation were carried out. The samples exhibited relatively high resistance to the generated plasma streams. The practical work indicated a loss of about 1.54 mg per plasma focus discharge. The computer model calculations gave a weight loss one magnitude greater. An attempt to explain this discrepancy is given in the paper.