TY - CONF A1 - Bruno, Giovanni A1 - Cabeza, Sandra T1 - Neutron diffraction: the forgotten non-destructive technique for residual stress analysis … and more N2 - 3-D Stress Analysis (Bulk) Stress mapping Thick (and thin) films & Interfaces Bulk high temperature Real time In-situ testing: Large sample environment (Stress rigs, Furnaces, …) Neutrons and Synchrotron Radiation allow all this because they are FASTER , DEEPER and MORE PRECISE than lab equipment (Flux)(Energy)(Parallel Beam) T2 - World Non Destructive Testing CY - München, Germany DA - 11.06.2016 KW - Neutron diffraction KW - Stress analysis PY - 2016 AN - OPUS4-38396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hejazi, Bardia A1 - Fritsch, Tobias A1 - Benz, Christopher A1 - Radtke, Lars A1 - Sander, Manuela A1 - Bruno, Giovanni T1 - In-situ very high cycle fatigue experiments of additively manufactured Ti-6Al-4V using X-ray computed tomography N2 - X-ray computed tomography (XCT) is an invaluable method for evaluating the properties and performance of components both during service and after failure in a non-destructive manner. XCT is particularly useful for the investigation of additively manufactured (AM) components, which often have production defects that are inherent to the manufacturing process, such as lack of fusion defects. Understanding the mechanisms of fatigue crack growth throughout the life cycle of such components is crucial and so to address this need, we designed and performed experiments to investigate the fatigue life and fatigue crack growth behavior of Ti-6Al-4V components under very high cycle fatigue (VHCF) testing. The titanium samples were additively manufactured with intentional internal defects to control crack initiation location. XCT of the component was carried out to identify crack initiation sites and characterize the dynamics of crack growth. The findings from this work will benefit industries that rely on the AM of titanium alloys, aiding in the improvement of component design and manufacturing processes. T2 - Alloys for additive manufacturing 2025 (AAMS 2025) CY - Neuchâtel, Switzerland DA - 02.09.2025 KW - X-ray computed tomography KW - Deep learning KW - Titanium alloy KW - Very high-cycle fatigue PY - 2025 DO - https://doi.org/10.5281/zenodo.15261296 AN - OPUS4-64096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - In-Situ Compression CT on Additively Manufactured in 625 Lattice Structures N2 - The porosity and the surface roughness are recently discussed problems for SLM parts. The influence of SLM process parameters on porosity is well studied for different materials. Nevertheless, the build angle (i.e. the angle between part orientation and build plate) needs to be understood as an additional SLM process parameter, as it has been shown, that the microstructure and hence the mechanical performance of various materials depend on the build angle. The inherent build angle of each strut as a part of a lattice structure is the motivation to investigate the influence of the build angle on the porosity and roughness on round-shaped (1 mm diameter) struts by means of CT. Conventional Coordinate Measuring Machine (CMM) has the limitation towards small and round shaped samples. The need for Computed Tomography (CT) regarding investigations of SLM parts will increase because no other non-destructive technique allows the assessment of complex geometries with inner laying surfaces. We used CT to assess the pores and the strut surface. Seven struts out of the nickel alloy Inconel 625 with build angles from 30° to 90° were studied. It was found that the number of pores is smaller, and the size of pores is larger for the 90° strut. In case of 30° strut, the number of pores is increased towards down-skin side, additionally, this strut orientation showed to have the largest number of attached powder particles. The elongated pores exist exclusively near the strut surface. While the roughness at the down-skin surface is highly depending of the biud angle, the roughness at the up-skin surface is the same for all struts. The mechanisms of pore and surface roughness formation is not mainly driven by gravity. T2 - ISAM Konferenz 2019 CY - Dresden, Germany DA - 29.01.2019 KW - Computed Tomography KW - Additive Manufacturing KW - Metals KW - Microstructure PY - 2019 AN - OPUS4-47327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bruno, Giovanni A1 - Buljak, V. T1 - Numerical modeling of thermally induced microcracking in porous ceramics: An approach using cohesive elements N2 - A numerical framework is developed to study the hysteresis of elastic properties of porous ceramics as a function of temperature. The developed numerical model is capable of employing experimentally measured crystallographic orientation distribution and coefficient of thermal expansion values. For realistic modeling of the microstructure, Voronoi polygons are used to generate polycrystalline grains. Some grains are considered as voids, to simulate the material porosity. To model intercrystalline cracking, cohesive elements are inserted along grain boundaries. Crack healing (recovery of the initial properties) upon closure is taken into account with special cohesive elements implemented in the commercial code ABAQUS. The numerical model can be used to estimate fracture properties governing the cohesive behavior through inverse analysis procedure. The model is applied to a porous cordierite ceramic. The obtained fracture properties are further used to successfully simulate general non-linear macroscopic stress-strain curves of cordierite, thereby validating the model. KW - Interfacial strength KW - Cordierite KW - Young’s modulus KW - Thermal expansion KW - Hysteresis KW - Inverse analysis KW - Cohesive finite elements PY - 2018 DO - https://doi.org/10.1016/j.jeurceramsoc.2018.03.041 SN - 0955-2219 VL - 38 IS - 11 SP - 4099 EP - 4108 PB - Elsevier Ltd. AN - OPUS4-45117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Applications of X-ray refraction to non-destructive characterization of and composites T2 - 14th International Conference of the European Ceramic Society CY - Toledo, Spain DA - 2015-06-21 PY - 2015 AN - OPUS4-33974 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - A few Aspects of the Current Understanding of DPF Materials Thermal and Mechanical Properties N2 - Bi-continuous porous ceramics for filtration applications possess a particularly complicated microstructure, whereby porosity and solid matter are intermingled. Moreover, they very often display a microcrack network, resulting from the strong anisotropy of the microscopic coefficient of thermal expansion (CTE). Mechanical, thermal, and filtration properties, they all strongly depend on the morphology of both solid matter and porosity, and on the degree of microcracking (also, the microcrack density), which is in its turn tightened to the grain size. Recent industrial and academic research has enormously progressed in understanding the microstructure-property-performance relationships existing in these complicated materials: - Using 3D computed tomography (CT) at different resolutions, and several X-ray refraction-based techniques, porosity and pore orientation could be quantitatively evaluated (in the example of cordierite). - Neutron and X-ray Diffraction has been instrumental to disclose a) the non-linear character of the stress-strain response, and b) the negative CTE of these materials, and its consequences on the materials properties; - Analytical and numerical models have been elaborated to rationalize these behaviours in terms of microcracking and microstructural features. Here these results will be reviewed, and a outlook at (some of the) outstanding problems will be given. T2 - HELSMAC CY - Cambridge UK DA - 7.04.2016 KW - Thermal KW - Materials PY - 2016 AN - OPUS4-35752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Evaluating Porosity in Cordierite DPF Materials: Advanced X-ray Techniques and New Statistical Anlaysis Methods T2 - CIMTEC 2014 CY - Montecatine Terme, Italy DA - 2014-06-08 PY - 2014 AN - OPUS4-30875 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Analyse von Schädigungsprozessen in Beton - Was leistet die CT? Teil1: Einblick in die Computertomographie N2 - Ein Nachteil der klassischen Durchstrahlungstechnik mit Röntgenstrahlen ist die, in der Abbildung des Untersuchungsobjektes, fehlende Tiefeninformation. Die Anwendung von radiografischen Verfahren, die das Objekt unter zwei oder mehreren Winkelpositionen durchstrahlen, erlauben die Rekonstruktion räumlicher Abbildungen. Dazu zählen Stereoradiografie, Translations- und Rotationslaminographie. Bei der Computertomographie erfolgt die Durchstrahlung unter einem Winkelbereich von 180° oder 360°. Die dabei aufgenommenen Projektionen werden anschließend durch Anwendung der Fourier Transformation und der gefilterten Rückprojektion zu einem 3D-Bilddatensatz rekonstruiert. Verschiedene systembedingte Artefakte, die das Ergebnis negativ beeinflussen können, lassen sich durch geeignete Meß- und Rekonstruktionsparameter, sowie einer nachfolgende Bildverarbeitung eliminieren oder reduzieren. T2 - Summer School im Rahmen des DFG Schwerpunktprogramms 2020 "Zyklische Schädigungsprozesse in Hochleistungsbetonen im Experimental-Virtual-Lab" CY - Hotel Park Soltau, Soltau, Germany DA - 25.06.2018 KW - Computertomographie KW - Durchstrahlungsverfahren KW - Bildverarbeitung KW - Rekonstruktionsverfahren KW - Bildartefakte PY - 2018 AN - OPUS4-45432 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Characterization of Additive Manufacturing Materials at BAM N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread equally holds for industrial and academic research and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. Examples of micro-structured inhomogeneous materials will be given, such as Composites, Ceramics, Concrete, and Additively manufactured parts. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces. Additionally, I will show how Neutron Diffraction, which is extremely well suited to the study of internal stresses, both residual and under external load, can well be coupled to the microstructural framework gained by CT, allowing understanding the microstructure-property relationships in materials. Finally, I will show that BAM is very active in standardization and certification, including production of Reference Materials and Methods. T2 - Skoltech Determination of the microscopic residual stress CY - Moscow, Russia DA - 20.11.2019 KW - Additive Manufacturing KW - Computed Tomography KW - Neutron Diffraction KW - X-ray refraction techniques KW - Composites PY - 2019 AN - OPUS4-49929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Evaluating Porosity and Properties in Diesel Particulate Filter Ceramics: a Problem to solve with Neutrons and Synchrotron Radiation T2 - Industrie Workshop HZB CY - Berlin, Germany DA - 2013-12-03 PY - 2013 AN - OPUS4-31320 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -