TY - CONF A1 - Ávila Calderón, Luis T1 - Creep Behavior of Stainless Steel 316L Manufactured by Laser Powder Bed Fusion N2 - Metal additive manufacturing (Metal AM) continues to gain momentum. Many companies explore the manufacturing of innovative products, including components for safety critical applications. Despite the intensive research of recent years, a fundamental understanding of the process‑structure‑property relationships remains challenging due to, i.a., the inherently complex and highly hierarchical microstructures arising from the wide range of build process parameter variability. This contribution presents the resu lts of an experimental study on the creep behavior of an austenitic 316L stainless steel produced by laser powder bed fusion (PBF LB/M/316L) with an emphasis on understanding the effects of microstructure on creep mechanisms. Hot tensile tests and constant force creep tests at 600 °C and 650 °C, X ray computed tomography, as well as optical and electron microscopy were performed. The produced PBF LB/M/316L exhibits a low void population 0.01 %) resulting from the manufacturing parameters used and which a llowed us to understand the effects of other microstructural aspects on creep behavior, e.g., grain morphology and dislocation substructure. A hot‑rolled variant of 316L hwas also tested as a reference. The produced PBF LB/M/316L possesses shorter primary and secondary creep stages and times to rupture and smaller creep stress exponents than the hot‑rolled variant. Overall, the creep damage is more extensive in the PBF LB/M/316L and is characterized as predominantly intergranular. It is considered that the damage behavior is mainly impacted by the formation of precipitates at the grain boundaries combined with their unfavorable orientation. The dislocation substructure and local elemental segregation appear to have a decisive impact on the overall creep behavior. T2 - 16th International Conference on Creep and Fracture of Engineering Materials and Structures CY - Bangalore, India DA - 28.07.2024 KW - AGIL KW - 316L KW - Additive Manufacturing KW - Creep KW - Microstructure evolution PY - 2024 AN - OPUS4-60839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hickel, Tilmann A1 - Richter, Silke A1 - Bitzek, E. A1 - Ávila Calderón, Luis A1 - Gedsun, A. A1 - Forti, M. A1 - Hammerschmidt, T. A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - NFDI-MatWerk/IUC02 Definition for Reference Data of Materials N2 - This definition was agreed within the infrastructure use case IUC02 “Framework for curation and distribution of reference datasets” of the consortium NFDI-MatWerk. It is broadly formulated to cover experimental and simulation MSE data and will be developed further in agreement with the MSE community. KW - Referenzdaten KW - Digitalisierung KW - NFDI-MatWerk KW - Research Data Management KW - Reference Data PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611688 DO - https://doi.org/10.5281/zenodo.11667673 PB - Zenodo CY - Geneva AN - OPUS4-61168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ávila Calderón, Luis A1 - Schriever, Sina T1 - BAM Reference Data: Creep of Single-Crystal Ni-Based Superalloy CMSX-6 N2 - This publication provides comprehensive metadata and test results of constant force creep tests according to DIN EN ISO 204:2019-4 on the single crystal Ni-based superalloy CMSX-6 at T = 980 °C and initial stresses between 140 MPa and 230 MPa. The tests were carried out in an accredited test laboratory using calibrated measuring equipment. The data were audited and are BAM reference data. KW - NFDI-MatWerk KW - Digitalisierung KW - CMSX-6 KW - Creep KW - Reference Data KW - Referenzdaten KW - Ni-Based Superalloy PY - 2024 DO - https://doi.org/10.5281/zenodo.13937986 PB - Zenodo CY - Geneva AN - OPUS4-61649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ávila Calderón, Luis A1 - Shakeel, Y. A1 - Schriever, Sina A1 - Gedsun, A. A1 - Forti, M. A1 - Jordan, Hans A1 - Han, Ying A1 - Baer, O. A1 - Aversa, R. A1 - Olbricht, Jürgen A1 - Hammerschmidt, T. A1 - Hickel, T. A1 - Skrotzki, Birgit T1 - NFDI-MatWerk/IUC02 Data schema for creep data of Ni-based superalloys including a comprehensive documentation of test results and metadata N2 - This data schema was developed within the infrastructure use case IUC02: “Framework for curation and distribution of reference datasets” of the consortium NFDI-MatWerk. It intends to define a structured approach for collecting all required information on a creep experiment using the established terminology of the respective test standard ISO 204:2022 and additional terminology agreed upon by the domain experts. The individual entries are grouped according to their content type and sub-summarized under respective headlines, thereby suggesting a basic categorization and a related hierarchy of concepts. This hierarchy can be similarly applied to other test methods and different metallic (and other) materials. In version 1.1 some editorial and formal changes were made. KW - NFDI-MatWerk KW - Digitalisierung KW - Referenzdaten KW - Kriechen KW - Ni-based Superalloys PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611629 DO - https://doi.org/10.5281/zenodo.11668375 PB - Zenodo CY - Geneva AN - OPUS4-61162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Ávila Calderón, Luis T1 - Mechanisches Verhalten von additiv gefertigtem nichtrostendem Stahl X2CrNiMo17-12-2 (AISI 316L) und Vergleich zur konventionell gefertigten Variante T1 - Mechanical behavior of additively manufactured stainless steel X2CrNiMo17-12-2 (AISI 316L) and comparison with a conventionally manufactured variant N2 - Die additive Fertigung (AM) metallischer Werkstoffe ist eine Technologie, die zunehmend Gegenstand von Forschungsaktivitäten und industrieller Anwendung ist. Dennoch steht sie noch vor Herausforderungen, um eine breite Nutzung in sicherheitsrelevanten Anwendungen zu erreichen. Die Hauptgründe für die Verzögerung des technologischen Durchbruchs zugunsten von AM-Metallen gegenüber konventionell hergestellten Varianten sind das Fehlen eines tieferen Verständnisses der Prozess-Struktur-Eigenschafts-Beziehungen und die begrenzte Verfügbarkeit von Daten zu den Materialeigenschaften. In diesem Kontext stellt diese Arbeit einen Beitrag sowohl zum Verständnis der Prozess-Struktur-Eigenschafts-Beziehungen als auch zur Verbesserung der Datenlage von 316L dar, einem häufig als Konstruktionswerkstoff in verschiedenen Hochtemperaturbauteilen verwendeten Werkstoff. Die Arbeit legt den Fokus auf die mittels Laser-Pulverbettschmelzen hergestellte Werkstoffvariante, PBF-LB/M/316L. Eine konventionell hergestellte Variante, HR/316L, wurde auch untersucht. Bei PBF-LB/M/316L wurde zusätzlich der Effekt ausgewählter Wärmebehandlungen ausgewertet. Die Untersuchung umfasste die Charakterisierung der mechanischen Eigenschaften und der Verformungs- und Schädigungsmechanismen bei erhöhten Prüftemperaturen bei LCF und Kriechen, wo die Daten und Wissenslage am spärlichsten ist. Außerdem hat die untersuchte PBF-LB/M/316L-Wersktoffvariante einen geringen Porositätsgrad. Somit hat diese Arbeit die Mikrostruktur stärker in den Fokus genommen als die meisten bisher in der Literatur verfügbaren Studien. Die mechanische Prüfkampagne umfasste Zugversuche zwischen Raumtemperatur und 650 °C, LCF-Versuche zwischen Raumtemperatur und 600 °C sowie Kriechversuche bei 600 °C und 650 °C. In Ermangelung konkreter Richtlinien und Normen wurde die Charakterisierung zumeist anhand der bestehenden internationalen Prüfnormen und Probengeometrien durchgeführt. Aus jedem dieser Prüfverfahren wurden die entsprechenden Festigkeits- und Verformungskennwerte ermittelt. Darüber hinaus wurde mit Hilfe gezielter mikrostruktureller Untersuchungen ein Beitrag zum Verständnis des Zusammenhangs zwischen der Mikrostruktur und den mechanischen Eigenschaften in Bezug auf die Verformungs- und Schädigungsmechanismen geleistet. Die Dehngrenze von PBF-LB/M/316L ist etwa doppelt so hoch wie die von HR/316L und dieser Trend setzt sich mit ansteigender Prüftemperatur fort. Die Bruchdehnung ist bei allen Prüftemperaturen geringer. PBF-LB/M/316L weist über den größten Teil der Ermüdungslebensdauer vor allem bei Raumtemperatur höhere zyklische Spannungen als HR/316L auf. Ausschließlich bei den kleinsten Dehnungs-schwingbreiten sind die Ermüdungslebensdauer ausgeprägt kürzer. Das Wechselverformungsverhalten von PBF-LB/M/316L ist durch eine Anfangsverfestigung gefolgt von einer kontinuierlichen Entfestigung charakterisiert, welche bis zum Auftreten der zum Versagen führenden Entfestigung stattfindet. Die Kriechbruchzeiten und die Dauer jeder Kriechphase sind bei allen Kombinationen von Prüfparametern bei PBF-LB/M/316 kürzer als bei HR/316L. Die Spannungsabhängigkeit von PBF-LB/M/316L ist im Vergleich zu HR/316L geringer und die Duktilität beim Kriechen kleiner. Die minimale Kriechrate wird bei allen geprüften Parameterkombinationen bei deutlich geringeren Kriechdehnungen erreicht. Eine Wärmebehandlung bei 450 °C / 4 h bewirkt keine wesentliche Änderungen der Mikrostruktur und Zugversuchseigenschaften. Eine zusätzliche Wärmebehandlung bei 900 °C / 1 h verursacht eine Abnahme der Dehngrenze des PBF-LB/M/316L. Diese blieb aber immer noch um den Faktor 1,5x höher als bei HR/316L. Die Verformungsmerkmale wurden kaum davon beeinflusst. Bezüglich des Kriechverhaltens hat die Wärmebehandlung bei 900 °C / 1 h längere sekundäre und tertiäre Kriechstadien bewirkt und die Kriechdehnung hat sich signifikant erhöht. Die Bruchbilder unterscheiden sich generell nicht nur aber vor allem mit ansteigender Prüftemperatur, bei der bei PBF-LB/M/316L oft interkristalline Rissbildung beobachtet wurde. Die Zellstruktur trägt als der Hauptfaktor zu den unterschiedlichen mechanischen Eigenschaften im Vergleich zur HR/316L-Variante bei. Darüber hinaus spielen mutmaßlich die Kornmorphologie, die Stapelfehlerenergie und der Stickstoffgehalt eine Rolle. N2 - Metal additive manufacturing (AM) is a technology that is increasingly the subject of research activities and industrial applications. However, it still faces challenges to achieve widespread use in safety-relevant applications. The main reasons for the delay of this technological breakthrough in favor of AM metals over conventionally manufactured variants are the lack of a deeper understanding of process-structure-property relationships and the limited availability of data on material properties. In this context, this work contributes to both achieving a better understanding of process-structure-property relationships and the improvement of data for 316L, an alloy frequently used as a structural material in various high-temperature components. The work focuses on a material variant produced by laser pow-der bed fusion, PBF-LB/M/316L. A conventionally produced variant, HR/316L, was also investigated. For PBF-LB/M/316L, the effect of selected heat treatments was also evaluated. The investigation included the characterization of the mechanical properties and the related deformation and damage mechanisms at elevated test temperatures in LCF and creep, where data and knowledge are scarce. The PBF-LB/M/316L variant studied has a low degree of porosity. Thus, this work is more focused on the microstructure than most studies available in the literature. The mechanical test campaign included tensile tests between room temperature and 650 °C, LCF tests between room temperature and 600 °C, and creep tests at 600 °C and 650 °C. In the absence of concrete guidelines and standards for testing of AM metals, the characterization mostly took place using existing international test standards and specimen geometries. From each of the test methods, corresponding strength, and deformation characteristic values were determined. In addition, targeted microstructural investigations contributed to understanding the relationship between the microstructure and the mechanical properties in terms of deformation and damage mechanisms. The proof stress of PBF-LB/M/316L is about twice that of HR/316L. This trend remains with increasing test temperature. The elongation after fracture is lower at all test temperatures. Regarding LCF, PBF-LB/M/316L exhibits higher cyclic stresses than HR/316L for most of the fatigue life, especially at room temperature. Exclusively at the smallest strain amplitudes, the fatigue lives of PBF-LB/M/316L are markedly shorter than in HR/316L. The cyclic stress-strain deformation behavior of PBF-LB/M/316L features an initial strain hardening followed by a continuous softening, which occurs until the softening leading to failure takes place. The creep rupture times and the duration of each creep stage are shorter for PBF-LB/M/316 than for HR/316L for all combinations of test parameters. The stress dependence of PBF-LB/M/316L is lower, and the creep ductility is smaller compared to HR/316L. The minimum creep rate is reached at significantly lower creep extensions for all parameter combinations tested. A heat treatment at 450 °C / 4 h did not cause significant changes in the microstructure and tensile behavior. An additional heat treatment at 900 °C / 1 h caused a decrease in the proof stress of PBF-LB/M/316L. However, it still remained higher than the one of HR/316L by a factor of 1.5x. The deformation characteristics were hardly affected. Regarding the creep behavior, this latter heat treatment at 900 °C / 1 h caused longer secondary and tertiary creep stages, and the creep strain increased significantly. The fracture characteristics generally differed, which happened not only but especially with increasing test temperature, where intergranular cracking often took place in PBF-LB/M/316L. The cellular structure is considered the main factor contributing to the different mechanical properties compared to the HR/316L variant. In addition, grain morphology, stacking fault energy, and nitrogen content might play a role. KW - AGIL KW - Additive Fertigung KW - Laser-Pulverbettschmelzen KW - Mikrostrukturentwicklung KW - 316L KW - LCF KW - Kriechen KW - Additive Manufacturing KW - Microstructure KW - Mechanical Properties KW - Mechanische Eigenschaften PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597143 DO - https://doi.org/10.14279/depositonce-19828 SP - 1 EP - 190 CY - Berlin AN - OPUS4-59714 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Creep Behavior of Stainless Steel 316L Manufactured by Laser Powder Bed Fusion N2 - This contribution presents the results of an experimental study on the creep behavior of an austenitic 316L stainless steel produced by laser powder bed fusion (PBF-LB/M/316L) with an emphasis on understanding the effects of microstructure on the creep mechanisms. Hot tensile tests and constant force creep tests at 600 °C and 650 °C, X-ray computed tomography, as well as optical and electron microscopy were performed. The produced PBF-LB/M/316L exhibits a low void population (< 0.01 %) resulting from the manufacturing parameters used and which allowed us to understand the effects of other microstructural aspects on creep behavior, e.g., grain morphology and dislocation substructure. A hot‑rolled variant of 316L was also tested as a reference. T2 - International Materials Science and Engineering Congress - MSE 2024 CY - Darmstadt, Germany DA - 24.09.2024 KW - AGIL KW - Additive Fertigung KW - Mikrostruktur KW - Mikrostrukturentwicklung KW - Kriechen KW - Kriechschädigung PY - 2024 AN - OPUS4-61169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Microstructure Based Study on the Low Cycle Fatigue Behavior of Stainless Steel 316L manufactured by Laser Powder Bed Fusion N2 - Due to the advantages of Laser Powder Bed Fusion (PBF-LB), i.e., design freedom and the possibility to manufacture parts with filigree structures, and the considerable amount of knowledge available for 316L in its conventional variant, the mechanical behavior, and related microstructure-property relationships of PBF-LB/316L are increasingly subject of research. However, many aspects regarding the - application-relevant - mechanical behavior at high temperatures are not yet fully understood. Here, we present the results of an experimental study on the LCF behavior of PBF-LB/316L featuring a low defect population, which makes this study more microstructure-focused than most of the studies in the literature. The LCF tests were performed between room temperature (RT) and 600 °C. The mechanical response is characterized by strain-life curves, and hysteresis and cyclic deformation curves. The damage and deformation mechanisms are studied with X-ray computed tomography, and optical and electron microscopy. The PBF-LB/M/316L was heat treated at 450 °C for 4 h, and a hot‑rolled (HR) 316L variant with a fully recrystallized equiaxed microstructure was tested as a reference. Besides, selected investigations were performed after a subsequent heat treatment at 900 °C for 1 h. The PBF-LB/316L exhibits higher cyclic stresses than HR/316L for most of the fatigue life, especially at room temperature. At the smallest strain amplitudes, the fatigue lives of PBF-LB/M/316L are markedly shorter than in HR/316L. The main damage mechanisms are multiple cracking at slip bands (RT) and intergranular cracking (600 °C). Neither the melt pool boundaries nor the gas porosity have a significant influence on the LCF damage mechanism. The cyclic stress-strain deformation behavior of PBF-LB/M/316L features an initial hardening followed by a continuous softening. The additional heat treatment at 900 °C for 1 h led to decreased cyclic stresses, and a longer fatigue life. T2 - 4th Symposium on Materials and Additive Manufacturing CY - Berlin, Germany DA - 12.06.2024 KW - AGIL KW - 316L KW - Microstructure KW - Low Cycle Fatigue KW - Heat Treatment KW - Laser Poeder Bed Fusion PY - 2024 AN - OPUS4-60432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Piesker, Benjamin A1 - Ávila Calderón, Luis A1 - Mohr, Gunther A1 - Rehmer, Birgit A1 - Agudo Jácome, Leonardo A1 - Hilgenberg, Kai A1 - Evans, Alexander A1 - Skrotzki, Birgit T1 - Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature N2 - This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters. KW - Additive manufacturing KW - Fatigue damage KW - Heat treatment KW - Inconel 718 KW - Laser powder bed fusion KW - Low-cycle fatigue KW - Tensile strength PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599316 DO - https://doi.org/10.1002/adem.202302122 SN - 1527-2648 SP - 1 EP - 17 PB - Wiley AN - OPUS4-59931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Research Data Management for Creep Reference Data of Ni Based Superalloys N2 - In times of digital data processing and sharing, a central challenge for the Materials Science and Engineering (MSE) community is the complete digital representation of materials, including their relevant processing and microstructure details and the resulting properties. This digital representation, supported by digital infrastructures, enables entirely new qualities of collaborative work and is central to how we will conduct MSE research and develop products in the future. The main challenges are the composition, shaping, and description of the data so that it can be easily interpreted, trusted, and re-used. This presentation introduces our current effort to develop a best practice framework for generating and distributing creep reference datasets for Ni-based superalloys, which builds on previous approaches. Researchers can use such datasets to compare their own experimental or simulation results, used, for instance, to perform simulation-based alloy design and optimization or in the verification of the own testing equipment. The concept includes building an easily accessible digital infrastructure to annotate and discover the datasets and the integration of an ontology that aligns with the necessary metadata schema. With the help of an ontology, the reference dataset for creep can be semantically described, thus enabling the digital representation and reusage of shared concepts from domain experts and the community. To achieve this, it is necessary to establish a defined vocabulary with corresponding relations and annotations. The interplay between a digital infrastructure, the agreement on the necessary metadata and related metadata schema, and an underlying ontology will ensure that data and results can be easily shared, taken up, and re-used, thus fulfilling the FAIR principles (Findable, Accessible, Interoperable, Reusable). Furthermore, we aim to develop a widely accepted definition of reference data and data quality levels and to reach a self-supported community process. We intend to motivate the discussion about reference material datasets, necessary metadata, and future collaborations within the creep community. T2 - 16th International Conference on Creep and Fracture of Engineering Materials and Structures CY - Bangalore, India DA - 28.07.2024 KW - Reference Data KW - Creep KW - Data schema KW - Research Data Management PY - 2024 AN - OPUS4-60837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Framework for Curation and Distribution of Reference Datasets on the Example of Creep Data of Ni- Based Superalloys N2 - This presentation introduces our current effort to develop a best practice framework for generating and distributing MSE reference datasets using creep data of Ni-based superalloys as an example, building on previous approaches. Such reference datasets can be used in the verification of testing equipment or to compare experimental or simulation results among different laboratories or collaborative centers. Our framework concept, for reference data, includes the generation of the data along with an agreement on the necessary metadata, considering the intended usage, and the integration into an easily accessible digital infrastructure to annotate and discover/distribute the datasets using a metadata schema accordingly aligned to a domain ontology. T2 - International Materials Science and Engineering Congress - MSE 2024 CY - Darmstadt, Germany DA - 24.09.2024 KW - Referenzdaten KW - Digitalisierung KW - Data schema KW - NFDI-MatWerk KW - Datenschema KW - FAIR PY - 2024 AN - OPUS4-61175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -