Humankind will be facing dramatic challenges during the upcoming decades. On the one hand, the world population is expected to increase from 7.8 billion people (2020) to about 9.7 billion by 2050. At the same time, the annual total energy consumption will rise from 390 to more than 600 quadrillion British thermal units. On the other hand, heat and exhaust emission must be reduced to limit global warming. Hence, in order to achieve carbon neutrality by 2050, as stated in the Paris agreement, there is an indispensable need for large-scale and clean power plants. Indeed, a vast number of today’s and tomorrow’s leading technologies in power generation rely on the safe and efficient use of high-temperature materials and devices. For instance, advancement of superalloys in individual and assembled components for gas turbines in solar-hybrid combined-cycle gas turbine power plants guarantees reliable electrical power supply for the predicted increasing world population. Further development of novel advanced high-performance materials as well as the design-material-process-performance optimization are fundamental aspects to achieve a considerable energy efficiency improvement of such applications. Consequently, this is the ultimate basis for reaching carbon neutrality.
The project ‘topAM’ will deliver a significant materials science and engineering contribution to this global challenge, as it provides novel nanostructured metallic materials to be assembled to complex-shaped structures by additive manufacturing (AM, also known as 3D printing). It will significantly contribute to strengthening Europe’s industry with respect to employment and turnover in the fields of process engineering and to establishing new non-ferrous and ferrous alloying strategies. Specifically, topAM targets the development of novel nano-oxide/nitride-dispersoid strengthened (ODS) high-temperature alloys on Fe, Ni, and NiCu basis for topologically optimized and additively manufactured gas burner heads and high-temperature heat exchangers components as examples for industrially relevant applications in extreme and highly aggressive environments. These novel materials will allow for operation of the devices in extreme and fluctuating atmospheres to increase energy efficiency for future low-carbon technologies, while reducing maintenance intervals and shut down periods by increasing their life-time. For instance, low-emission steam generators in boilers incorporating flue gas recirculation rely on the target devices of the project, they are essential for high-efficiency power plants and therefore are considered by the European Commission (EC) in the Best Available Techniques reference documents. Despite the striking advantages of both ODS alloys and AM separately, the application of ODS alloys in combination with AM has not yet been scaled up to industrial applications and real conditions for aggressive high-temperature environments and challenging mechanical operational demands. topAM will close the existing gap for the first time by an innovative combination of:
The project consortium allows for evaluation and optimization of the complete value chain from computational material and component design to raw material production and processing to experimental verification and lifecycle assessment resulting in the impacts listed below.
Reduction of CO2 emissions and resource utilization by 20% and reduced material raste by >40%
Increased lifetime of the equipment by >20%
Significant contribution to achieving energy efficiency improvement of 30%
Tweets from @SPIRE2030. Tweets from @topAMproject.
Europe’s industry is facing many challenges such as global competition and the big change towards energy and resource efficiency. topAM can contribute to these demands by development and application of novel processing routes for new oxide-dispersoid strengthened (ODS) alloys on FeCrAl, Ni and NiCu basis. Novel ODS materials offer a clear advantage for the process industry by manufacturing, e.g. topology-optimized, sensor-integrated high temperature devices (gas burner heads, heat exchangers) that are exposed to aggressive environments. Alloy and process development will be targeted by an advanced integrated computational materials engineering (ICME) approach combining computational thermodynamics, microstructure and process simulation to contribute to save time, raw materials and increase the component’s lifetime. Physical alloy production will be realized by combining nanotechnologies to aggregate ODS composites with laser-powder bed fusion and post-processing. The ICME approach will be complemented by comprehensive materials characterization and intensive testing of components under industrially relevant in-service conditions. This strategy allows to gain a deeper understanding of the process-microstructure-properties relationships and to quantify the improved functionalities, properties and life cycle assessment. This will promote cost reduction, improved energy efficiency and superior properties combined with a significant lifetime increase. The consortium consists of users, materials suppliers and research institutes that are world leading in the fields relevant for this proposal, which guarantees efficient, high-level, application-oriented execution of topAM. The industrial project partners, in particular the SMEs, will achieve higher competitiveness due to their strategic position in the value chain of materials processing, e.g. powder production, to strengthen Europe's leading position in the emerging technology field of AM in a unique combination with ICME.
The development of nano-oxide/nitride-dispersoid strengthened (ODS) alloys on Fe, Ni and NiCu basis with tailored properties under extreme (i.e. thermal, mechanical and corrosive) service conditions to be used for additively manufactured gas burner heads and high-temperature heat exchanger components:
The overall strategy of topAM is based on bringing together leading materials and computer scientists, production engineers, chemists and physicists in order to develop novel materials and components produced via a new processing route by strongly interdisciplinary collaboration. The partners of the consortium come together based on their project-relevant expertise, previous bilateral collaborations and stakeholder knowledge in the fields ICME, alloy development for AM, nanotechnologies for powder modification, high-temperature materials behaviour, and surface modification. The consortium consists of:
The consortium partners have collaborated in various national and international research projects to-date. The topAM management structure is outlined below.
As stated in the EC’s Best Available Techniques reference document for Large Combustion Plants, further increase of process efficiency and reduction of NOX and CO2 emissions are the main targets for the future development of power plants, which will guarantee reliable world-wide energy supply and contribute to reaching carbon neutrality by 2050. Most power plants operate using a steam process that uses the fuel energy to generate steam at high pressure and temperature, both necessary for high efficiency. In this context, boilers are critical subsystems that ensure the efficiency of power plants due to controlled water/steam circulation, and they are of highest importance in direct processes including steam turbines, as well as in indirect processes such as steam reforming plants, like steam reformer methanol or ethylene crackers, for production of process gases. On the other hand, the technical reliability and durability of boilers depends strongly on two components, namely burners for controlling the temperature of water/steam and heat exchangers for heat transfer. Both components are subjected to fluctuating and extreme conditions in terms of high temperatures (815-1250 °C burner head, >675 °C heat exchanger), aggressive environments (e.g. CH4, H2, CO, H2S, O2, air), and mechanical loading. Hence, the main goal of topAM, the development of high-temperature ODS alloys with excellent creep and oxidation behaviour, directly contributes to increased plant efficiency and performance.
Using currently established materials (e.g. Monel-type Alloy 400 for heat exchangers or Kanthal® APMT and N18 for gas burner heads) and processes for producing gas burner heads and heat exchangers (both produced by casting, post-processing, machining and joining), these components cannot be improved sufficiently to boost the energy efficiency of present and future energy-transforming systems. With respect to the alloys to be used, the development will be directed towards modification of the base material and towards addition to the base material (nano-sized oxides/nitrides). While the base material influences mainly the functional properties (i.e. increased oxidation re- sistance due to increased Cr or Cu contents in the Fe- and NiCu-based alloys, improved processability during LPBF (due to minimizing the solidification interval to prevent cracking, etc.), the nano-sized oxides/ni- trides strongly improve the mechanical properties in terms of high strength and creep resistance. As compared to other alloying concepts (without ODS), especially the mechanical properties are strongly im- proved due to increased stability of the microstructure (grain boundary pinning prevents grain growth and the low coarsening rate of oxides due to their low interfacial energy) and effective blocking of dislocations at high temperatures. This will result in a significantly increased lifetime, i.e. reduced damage of components. The improved materials will be combined with flexible production by LPBF to develop advanced components that withstand extreme conditions.
In contrast to conventional processing, the use of nanotechnologies for powder modification in combination with LPBF, as targeted in topAM, is characterized by the following advantages, specifically with respect to the processing of ODS alloys:
Hence, the processing approach used in topAM will allow for direct, energy-efficient production of ready-to-assemble, complex-shaped components with reliable properties and integrated sensors. Consequently, inservice component control via temperature, strain, and corrosion rate sensors enables reduced maintenance costs, avoidance of unexpected plant shutdowns due to abrupt failure of components and minimized constraints on industrial processing conditions.
topAM addresses the design of gas burner heads and heat exchangers by both extensive computational and experimental methods. On the computational side, the LPBF-specific redesign of the target components will be guided by computer-aided design (CAD) modelling combined with AI-assisted topology optimization. Here, machine learning (neural networks) will be applied to enable time-efficient component design. In addition, the design of the ODS high-temperature alloys for the AM parts is modelled by a rigorous ICME approach, i.e. linking materials models addressing multiple physical mechanisms on varying length scales, e.g. macroscopic melt pool, microstructure on μm-level, mesoscopic plasticity and macroscopic component performance. Due to the high dimensionality of the parameter space and hence a high number of influential factors during combined process and alloy design, the output resulting from the ICME approach will be used to train a data-driven model (Gaussian process regression model) to predict the process-structure-properties-performance linkages. The implementation of modelling concepts bridging various scales will allow for the adaptation of structural integrity concepts to maintain process reproducibility and operational safety during the whole product life cycle. The goal of topAM is the creation of a digital twin of the components including their microstructure evolution using ICME. The digital twins enable the generation of highly individualized, easily adaptable components and reduce the amount of experimental work. Parallel, complimentary experiments (e.g. multi-scale materials analytics, creep, wear and high-temperature corrosion testing) will be used to better understand the underlying phenomena active in these novel components, to deliver input data for and validate the simulations, and allow for life cycle assessment. Comparative studies using coated/uncoated specimens/components and various surface qualities will be performed to evaluate the alloys’ performance.
Covering of the whole process chain of AM for modified powders and derivation of process parameters for all steps of the process chain.
Powder production by gas atomization and powder modification by freeze granulation / mechanical alloying / internal oxidation or nitridation; thorough control of particle size distribution, flowability, particle roundness, etc.
Studies on the quality of LPBF-built parts by investigation of the relative density, microstructure, distortion, internal stresses, defects and identification of optimal parameter sets for the conjunction of powder properties and LPBF-process.
Performance of high temperature exposures in various environments by application of screening and selective further investigations; analyzation of corrosion products, corrosion kinetics and derivation of mechanisms, always in comparison with benchmark samples.
Performance of creep, tensile and HCF tests. Identification of damage mechanisms and comparison with benchmark samples.
Component design with sensor integration and successful LPBF of the generated CAD file.
Below are the achieved deliverables to-date that have resulted from the topAM project.
D9.1: Project management handbook, including quality assurance and risk management. M01.
D8.1: Communication and Dissemination Plan, including how and where results will be reported. M03.
D1.1: Specification sheet for high-temperature burner head (confidential), setting conditions and properties for the target alloys of the project. M05.
D1.2: Specification sheet for high temperature heat exchanger (confidential), setting conditions and properties for the target alloys of the project. M05.
D8.2: Data Management Plan (evolving document), including storage of data and longer term considerations. M06.
D8.3: Exploitation Plan (confidential, evolving document for peparative activities), including technology transfer aspects of the project. M06.
To be scheduled...
The following abstract has been accepted for the TMS 2022 meeting, February 27–March 3, 2022 in Anaheim, California, USA, in the Symposium: Environmental Degradation of Additively Manufactured Alloys.
Metal dusting resistance of additively manufactured Ni-based alloys: influence of post-processing surface and heat treatments
Metal dusting (MD) attack occurs in carbonaceous atmospheres (ac>1) and temperatures of 400-800°C, common in the downstream cooling stages of processing and syngas plants, and after an incubation period, causes rapid disintegration into fine coke particles. AM is of interest for MD applications as it could be used to replace corroded components on-demand, and where complex geometries would be beneficial. Advanced Ni-based alloy 699XA has been developed for MD environments and recently been adapted for AM processing. Alloy 699XA builds were tested under industrial MD conditions at 620°C for 1000 hours with different surface conditions and heat treatments. The build post-processing effects on the pit formation and MD resistance will be discussed in relation to the onset mechanisms and the results compared with conventional wrought Ni alloys. This ‘topAM’ project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 958192.
The success of topAM scientific and technological goals also depends on the impact in the relevant industries and its stakeholders. They are defined as parties with interest in topAM who impact or are impacted by the project’s results. The consortium has identified a list of stakeholders that are relevant to topAM. These are summarised in the following:
Industrial consignees: ODS powder users, plant operators, gas burner/heat exchanger users
Scientific community: universities, research institutes (e.g. HT corrosion), AM developers, mechanical property users
Associations: DECHEMA, SPIRE
Regulatory authorities and standard organizations: EU standardization organizations, e.g. CEN and CENELEC
Interested public: Visitors of conferences/fairs
The second topAM Briefing has been published! Our June 2022 issue has also been sent out via email to all project partners and the External Advisory Board. Additonally we have now set the following dates for the next project meeting:
The first topAM Briefing is published here! Our November 2021 issue was also sent out via email to all project partners.
For further information about this project, please contact: Dr. Ulrich Krupp at Krupp@iehk.rwth-aachen.de.
For additions/modifications to this website, please contact Dr. Emma White at email@example.com.