Florencia Malamud

• PhD
• PostDoc Position at Paul Scherrer Institute

This article developed an archaeometric examination of the brass sheathing remains recovered from two mid-19th-century shipwrecks, in Mexico: El Ángel site and the Black Warrior (1858), studied by the Vice-Directorate of Underwater Archaeology (SAS) of the National Institute of Anthropology and History (INAH) in collaboration with scholars from oth...

We demonstrate an approach to the reconstruction of scanning probe X-ray diffraction tomography data with anisotropic polycrystalline samples. The method involves reconstructing a voxel map containing an orientation distribution function in each voxel of a bulk 3D sample. By choosing a particular kind of basis functions, we can effectively utilize...

Energy‐efficient, safe, and reliable Li‐ion batteries (LIBs) are required for a wide range of applications. The introduction of ultra‐thick graphite anodes, desired for high energy densities, meets limitations in internal electrode transport properties, leading to detrimental consequences. Yet, there is a lack of experimental tools capable of provi...

Layer-wise laser-based additive manufacturing techniques offer immense versatility and flexibility in fabricating metallic composites with complex shapes. Interest in producing new multi-materials with advanced characteristics outpaces the available methods that provide insights into the bulk material formation, which in turn enables process and ma...

Energy efficient, safe and reliable Li-ion batteries (LIBs) are required for a wide range of applications. Charging capabilities of thick electrodes still holding their stored high-energy is a most desirable characteristic in future advanced LIBs. The introduction of ultra-thick graphite anode meets limitations in internal electrode transport prope...

We demonstrate a novel approach to the reconstruction of scanning probe x-ray diffraction tomography data with anisotropic poly crystalline samples. The method involves reconstructing a voxel map containing an orientation distribution function in each voxel of an extended 3D sample. This method differs from existing approaches by not relying on a p...

The effects of adding Si to Fe45−xMn30Cr10Co15Six high entropy alloys on martensitic transformation temperatures, structural parameters and strain energy is analyzed. Three different Si amounts are considered, 2, 4, and 6 atomic percent and results are compared with the alloy free of Si. It was verified using x-ray diffraction and energy dispersive...

Wavelength-resolved neutron transmission experiments are useful for characterizing the microstructure of macroscopic specimens with 2D spatial resolution perpendicular to the beam direction. The crystallographic texture can affect the neutron transmission in the thermal neutron energy range, which manifests as changes in the shape and height of Bra...

Multi-material laser powder-bed fusion (M2LPBF) is a novel additive manufacturing approach that makes it possible to print different materials along the built direction and within a single layer of a component. At the interface between the different materials, the deposited powders melt, mix and solidify very rapidly, than can produce a range of de...

In polycrystalline materials, the shape and height of Bragg edges observed in wavelength resolved neutron transmission experiments depend on the crystallographic texture. Previous works have proved the capacity of actual models to predict the transmission spectra once the texture of the material is known. In this work, we summarize the recent advan...

Many applications using neutron imaging for materials science use diffraction-based contrast to explore and understand the condition of the samples. Diffraction-based methods require wavelength resolution. The neutron imaging instrument ICON at Paul Scherrer Institut has, until recently, only provided this functionality using a velocity selector. W...

The determination of the amount and distribution of different phase fractions in additively manufactured shape memory alloys processed with laser powder bed fusion is crucial for understanding the correlation between processing parameters, microstructure, and mechanical properties. Neutron imaging techniques, such as Bragg edge imaging and polariza...

The advancement of laser-based metal additive manufacturing has enabled the production of near net shape complex geometries. Understanding the microstructural features of materials is crucial for accurate modeling of their mechanical behavior, particularly with regard to strain- or thermal-induced martensitic phase transformations in ferrous alloys...

The attenuation coefficient of textured materials presents a complex dependence on the preferred orientation with respect to the neutron beam. Presented here is an attenuation coefficient model to describe textured polycrystalline materials, based on a single-crystal to polycrystalline approach, aiming towards use in full-pattern least-squares refi...

Spatially resolved studies of crystalline structures, e.g. lattice spacings, are enabled by recording the transmitted spectra in neutron Bragg edge imaging. The recorded signals are, however, a result of through-thickness averaging of the probed specimen in the beam direction. Therefore, it is challenging to extract the strain distribution when the...

Spatially resolved neutron texture analyses were performed on several copper bolts used to fasten different wooden components of the hull of the Deltebre I (1813) shipwreck. Since 2008 this site has been the subject of a thorough archaeological study by the Catalan Centre for Underwater Archaeology of the Archaeological Museum of Catalonia. It has...

In this work we perform a neutron Bragg edge tomography of stainless steel 316L additive manufacturing samples, one as built via standard laser powder bed fusion, and one using the novel three-dimensional (3D) laser shock peening technique. First, we consider conventional attenuation tomography of the two samples by integrating the signal for neutr...

Lattice misfit in nickel-based superalloys is one of the important microstructural parameters that control their mechanical properties, such as creep behaviour at high temperatures. Here, energy-resolved neutron imaging experiments are performed at a spallation neutron source to determine the spatial variation of lattice misfit on a second-generati...

In: F. Cerezo Andreo and C. Pérez-Reverte Mañas (eds.), Book of Abstracts, I Congreso Iberoamericano de Arqueología Náutica y Subacuática, pp. 346-350. University of Cadiz, Cadiz, Spain. Available in: https://rodin.uca.es/xmlui/handle/10498/25256 [Access: 02.08.2021]

A novel method to estimate integral parameters of the orientation distribution function (ODF) in textured polycrystals from the wavelength-resolved neutron transmission is presented. It is based on the expression of the total coherent elastic cross section as a function of the Fourier coefficients of the ODF. This method is broken down in detail fo...

In this work we have investigated the influence of Ar sputtering pressure (PAr) in the magnetic properties of polycrystalline sputtered Fe0.89Ga0.11 thin films. The structural characterization shows that the samples are composed by several fiber-like crystallographic textures in which the fiber axis is always along the growth direction, whereas the...

In this work, we present the characterization of Ti sheathed MgB $_2$ wires prepared by PIT with two different cross-sections: circular and hexagonal. We determined the crystallographic texture of both the Ti sheath and the MgB $_2$ core by X-ray diffraction (XRD) pole figures. We evaluated the critical current density ( $J_c$ ) of the wires in...

Several strategies to increase the FCC austenite stability compared to BCC and HCP martensites have been tested and are discussed. The relative stability of the different phases was analyzed by studying the effects of: a) grain size, b) antiferromagnetic ordering of the austenite, c) thermal cycling through the FCC-HCP transition, d) plastic deform...

In this work, we present a systematic study on the relation between the elastic behavior and the structural properties of polycrystalline Fe0.89Ga0.11 thin films deposited on Si(100) substrates. By carrying out pole figure (PF) measurements, we determined the evolution of the texture components, residual stress and Young's modulus (Ys) as a functio...

In this note, we summarise the ongoing research on the Deltebre I (1813) shipwreck, highlighting especially the spatially resolved neutron texture analysis on the copper bolts used to fasten different wooden components of the hull’s structure of the ship. The texture results indicate that two methods were most likely used to manufacture the structu...

The effect of Cr on the fcc–hcp martensitic transformation in the Fe–Mn–Cr system has been discussed considering different aspects: (a) the relative phase stabilities, (b) the magnetic order of the fcc phase, (c) the structural parameters and volume change between fcc and hcp, (d) the driving force of the martensitic transformation and relevant the...

The transformation induced plasticity (TRIP) effect is investigated during a load path change using a cruciform sample. The transformation properties are followed by in-situ neutron diffraction derived from the central area of the cruciform sample. Additionally, the spatial distribution of the TRIP effect triggered by stress concentrations is visua...

High-Mn steels attract attention because of their various technological properties. These are mainly mechanical and functional, such as the shape-memory effect, high damping capacity, high strength with simultaneous large ductility, the TRIP/TWIP (transformation- and twinning-induced plasticity) effect, low cycle fatigue and high work hardening cap...

In this work we present a careful study on the relationship between the magnetic and structural properties of a highly magnetostrictive Fe0.89Ga0.11 (Fe-Ga) alloy deposited onto glass, Si and MgO substrates. When grown on glass, the films are polycrystalline with randomly oriented grains without any texture, while the ones on Si and MgO present pre...

By the use of several experimental techniques the difference in the Gibbs free energy between fcc austenite and hcp martensite has been determined for a wide range of compositions of Fe-Mn-Cr alloys where the martensitic transition takes place. Martensitic transformation temperatures were determined by dilatometry measurements, while the lattice pa...

The presence of texture in Ti sheathed MgB2 cables, induced by the manufacturing process, have been evaluated using XRD pole figures. Drawn monofilamentary and rolled multifilamentary cables have been compared in order to determine the effect of different deformation degrees arising from the thermo-mechanical treatments. Finally, the critical curre...

The reproducibility of the determination of crystallographic texture of Zr-based components by neutron diffraction has been studied through a small round-robin exercise, with the participation of texture and residual stress diffractometers from five international laboratories. Both constant-wavelength and polychromatic neutron beams have been used...

Fe-Mn-based alloys show the shape memory effect which is mainly related to the FCC-HCP martensitic transformation. Cr is one of the additional elements which improve the properties of these alloys. In the present work structural data are obtained for the FCC austenite, and both martensitic structures, HCP and BCC, for an extended composition range...

The spatial resolution achievable by a time-of-flight neutron strain scanner has been harnessed using a new data analysis methodology (NyRTex) to determine, nondestructively, the spatial variation of crystallographic texture in objects of cultural heritage. Previous studies on the crystallographic texture at the centre of three Napoleonic War era c...

Neutron diffraction techniques are suitable for volume texture analyses due to high penetration of thermal neutrons in most materials. We have implemented a new data analysis methodology that employed the spatial resolution achievable by a time-of-flight neutron strain scanner to non-destructively determine the crystallographic texture at selected...

The energy-resolved neutron transmission of mosaic crystals contains a series of dips in intensity, at specific neutron wavelengths defined by the orientation of the specimen in the neutron beam. This article presents a Rietveld type full-pattern analysis of neutron transmission experiments on mosaic crystals performed at spallation pulsed neutron...

A time-of-flight (TOF) neutron strain scanner is a white-beam instrument optimized to measure diffractograms at precise locations within bulky specimens, typically along two perpendicular sample orientations. Here, a method is proposed that exploits the spatial resolution (∼1 mm) provided by such an instrument to determine in a nondestructive manne...

The radiation in the X-ray range detected outside the vacuum chamber of the dense plasma focus (DPF) PACO, are produced on the anode zone. The zone of emission is studied in a shot-to-shot analysis, using pure deuterium as filling gas. We present a diagnostic method to determine the place and size of the hard X-ray source by image analysis of high...

An experimental study on the fluctuations in the instants of time and amplitudes of the peaks in the voltage, current time derivative, X-rays, and neutron signals during a 150-shot series in a 2 kJ Plasma Focus device is presented. The results show a reasonable correlation between the time of the voltage peak and that of X-ray emission, in agreemen...