In-situ investigation of the decomposition process in cold-rolled Nb53Ti47 alloy.

The multi-layer composite development primarily aims to develop and test the components of the next generation of hadron colliders (e.g., Large Hadron Collider - LHC) consisting of superconducting raw materials. Multilayer sheet is very similar to the commonly used NbTi wire products, a 2D version of the commercial wire. These composites consist of layers such as NbTi superconductor, Nb diffusion barrier (between NbTi and Cu) and Cu stabilizer. In ß-NbTi superconducting alloys, α-Ti precipitates are primary flux pinning centers that maintain stable superconductivity. A multi-step series of heat treatments and cold-forming processes can develop the flux pinning centers. Practically, this process means three heat treatments of constant period and temperature and drawing or rolling between the heat treatments. The study aimed to describe the behavior of the cold-rolled (ε = 3.35) Nb53Ti47w% alloys during isothermal heating at 673 K as a function of heating time. The processes during the aging were investigated by the in-situ XRD method in the heating chamber. The X-ray diffraction patterns were evaluated by Rietveld refinement. The thermally activated spinodal decomposition and precipitation processes were described based on the phases identified at the individual heat treatment steps and their lattice parameters. The in-situ study also revealed an increase in α-Ti precipitation with time and decomposition that co-occurs. This is the basic study that prepares the applicability of the alloy.

Dataset on full width at half maximum of residual stress measurement of electron beam welded high strength structural steels (S960QL and S960M) by X-ray diffraction method.

In this paper, we presented the dataset values of full width at half maximum (FWHM) with errors at each point corresponding to the value of longitudinal and transverse residual stress along the three lines for 14 points measured in the EBW welded joints (S960QL and S960M) of the related article [1]. This dataset is used to plot figures and describes their correspondence points with the interrelation of the residual stress graphs (Fig. 4) of the article [1]. The shape of the diffracted peak can be characterised in a simple way by the FWHM, which is the width in degree at half the peak height after background extraction. The measured width consist of instrumental and metallurgical broadening. The variation or increase in FWHM is resulted from the crystalline lattice defect e.g. solute foreign atoms, dislocations and grain boundary. Conversely, if we can determine the physical broadening, we get more information about the structure of the investigated material. In addition, the optical microscopic image of the base materials and weld microstructure are the other parts of the data. Diffraction data were collected using centreless X-ray diffraction (XRD) during in situ residual stress measurement of high strength structural steels S960QL and S960M. A more detailed interpretation of the data presented in this article is provided in article [1]. The presented data are produced as part of the main work entitled "Comparative evaluation of residual stresses in vacuum electron beam welded high strength steel S960QL and S960M butt joints [1]".

Estimation of Phase Ratio in Bulk, Textured TWIP/TRIP Steels from Pole Figures.

The volume fraction of austenite (γ), ε martensite and α' martensite is of key importance in the research of TWIP/TRIP steels. When mechanical loading is involved, the crystallographic texture also develops, which complicates X-ray diffraction-based phase ratio determination. The problem is more pronounced when only a couple, or only one Bragg-reflection can be measured. A solution for such cases is to determine the ratio of the phases based on the pole distribution function of a selected Bragg-reflection of the present phases. In this manuscript, this method is reconsidered for and applied to non-transmittable bulk specimens for the first time in the reflection mode of XRD pole figure measurements. First, the method was applied to a series of γ-α' powder mixtures. The results were compared to those obtained by the Rietveld method. Afterwards, the technique was applied to strongly textured, bulk TWIP/TRIP steel specimens which were tensile tested at different temperatures. It was shown that the results of the presented method were close to those of the Rietveld technique in the case of powder mixtures. The results of the tensile-tested steels revealed that the α' content increases with decreasing test temperatures, and the variation of the α' ratio correlates very well with the ultimate tensile strength versus the temperature, confirming the contribution of the α' content to the strength of TWIP/TRIP steels.