During the Bronze and Iron Ages, seven metals and about ten alloys were employed in the Western world. The manufacturing processes used by craftsmen (casting, hammering, finishing) for the copper base alloys are examined and discussed from the archaeological and metallurgical points of view. Some results obtained in Burgundy, dating from the 1st century BC to the 3rd century AD, permit tentative conclusions to be drawn regarding workshop organization and mass production.

Two shape memory steels of the types Fe-31Mn-6Si and Fe-18Mn-8Cr-5Ni-5Si have been used for the experimental study of the transformation plasticity associated in these steels with the martensitic transformation γ(fcc) → ε(hcp). This study shows that austenitic samples, submitted to small bending stresses, show transformation plasticity on cooling. The formation of oriented ε martensite and the volume change between the primary and the transformed phases are responsible for this behaviour. In Fe-Mn-Si types of steel, transformation plasticity is reversible by a mechanism of shape memory. In contrast with TRIP steels, the plastic strain in the steels studied disappears on heating. The degree of shape recovery depends on the type of steel and on the fact that the stress is maintained or released. In both cases, effects relative to stress induced martensite reversion are observed.

Classically, the simulation of primary recrystallization and grain growth starts from a theoretical microstructure defined numerically and characterized by a random texture distribution. The results obtained in this way represent well the overall behaviour of the material during annealing, but do not allow to obtain a local description, consistent with reality. In such procedures, a perfect homogeneity is assumed both for microstructure and for texture, which is generally not observed experimentally. For this reason, the authors have proposed in recent years to combine simulation and experimental observations; the calculation starts from the real microstructure characterized by TEM or by OIMTM. The first simulations of this kind carried out have shown that such an approach is feasible and has a great potential. These results are summarized and discussed in this paper. There are limits to this approach, related in particular to the lack of experimental data on the strain energies stored in the grains after deformation and on the energies and mobilities of grain boundaries.

Surface laser alloying can improve mechanical behaviour, particularly hardness, wear or corrosion resistance. Here, different boron coatings - boron carbides, boron, boron-iron or zirconia-boron mixtures - on a chromium-molybdenum steel are laser melted; the laser tracks show rather homogeneous microstructures; hardness increases with boron content and can reach about 1200 HV over a one millimeter depth with 5.7% boron, without the formation of the brittle phase FeB.

Efforts made since a few years in view of the integration of mechanical laws in numerical simulation now spread to friction behaviour. After presentation of the major laws available in the literature, a method permitting to obtain an empirical friction law is described. The validity of this approach is illustrated through the analysis of the tribological behaviours of three steel sheets: cold rolled, electro-galvanized and hot dip galvanized.

When welding a zinc coated steel sheet, the associated thermal cycle may activate diffusion and/or alloying reactions between steel and zinc. These reactions develop differently depending on the coating type (electro- or hot dip-galvanized, galvannealed). This in turn determines the chemical aggressiveness of the coating toward its environment, for example the copper electrodes used in spot welding.

Taking into account the mechanical properties of the different materials constituting a weld (mismatch effect) is necessary when dealing with defect assessment of structures with a crack located in a weld or near it. This paper is a synthesis of the work done in the past at Electricité de France on this topic in relation with other works done in France or around the world.

Several ferritic stabilized and austenitic stainless steels were investigated under cyclic high temperature corrosion conditions in order to assist material engineers in the choice of materials assigned to automotive exhaust systems. Cycle conditions were chosen to be representative of an actual vehicle use. The importance of spalling phenomena was confirmed. Due to their low thermal expansion coefficients, the ferritic stabilized grades behave fairly well, even in these rather severe high temperature conditions. The influence of nature and concentration in stabilizing elements (Ti, Nb) on the cyclic oxidation behaviour is pointed out.

This study concerns the inhibition of the corrosion of the aluminium alloy 3003 in a solution of 3% NaCl by Li+, Mg2+, MoO42-, NO2- and CrO42- ions. The methods used are the determination of the polarization curves and the metallographic examination of the surface condition. The results obtained show that the tested ions inhibit the corrosion process.The comparative study of the effect of these ions shows that the Mg2+ ions are the most efficient ones in the temperature range from 25 to 65°C. The inhibition efficiency increases with the concentration of these ions and reaches a maximum value of 86% for 5 × 10-2 alloy. As a consequence, the gap between pitting and corrosion potentials becomes larger. At 75°C, Mg2+ ions tend to stimulate corrosion of alloy 3003 in the chloride solution considered.