Periodic Reporting for period 3 - FunBlocks (Fundamental Building Blocks – Understanding plasticity in complex crystals based on their simplest, intergrown units)
Période du rapport: 2023-06-01 au 2024-11-30
New structural materials with higher strength and temperature capabilities are the key enablers of sustainable energy conversion and transport technology of the future.
The question is: How do we find those central high-performers combining high strength and the essential deformability giving safety in application?
It is the aim of FUNBLOCKS to provide the first systematic studies of plasticity mechanisms in the most fundamental building blocks of complex crystals. These will allow us to deduce the missing basic mechanisms and signatures of plasticity. FUNBLOCKS will take a new approach by studying the much simpler subunits that form the multitude of more complex crystals with large unit cells amongst the intermetallics. This has three major implications: i) the reduction to fundamental units allows sufficient time to unravel the major deformation mechanisms to the atomic level, ii) the recurrent nature of the few fundamental building blocks will allow a transfer of this knowledge to a large number of complex phases, and iii) together, this will enable data mining from the vast and largely unexplored phase space of intermetallics.
Therefore, the key aspect of FUNBLOCKS is to close the existing gap in knowledge and allow us to find promising new phases by elucidating the fundamental relationships between crystal structure and plasticity beyond what we know in simple metals. To identify and quantify the intrinsic mechanical properties of each subunit, state-of-the-art micromechanical testing techniques will be used. Transfer of data and verification of the central hypothesis, that fundamental units govern plasticity in complex crystals, will be achieved via additional alloyed crystals forming ternary variants of the binary structures.
Ultimately, FUNBLOCKS will answer fundamental questions in plasticity, most prominently the interplay of deformation and structure in complex crystals, and thereby support the development of new high performance materials.
The question is: How do we find those central high-performers combining high strength and the essential deformability giving safety in application?
It is the aim of FUNBLOCKS to provide the first systematic studies of plasticity mechanisms in the most fundamental building blocks of complex crystals. These will allow us to deduce the missing basic mechanisms and signatures of plasticity. FUNBLOCKS will take a new approach by studying the much simpler subunits that form the multitude of more complex crystals with large unit cells amongst the intermetallics. This has three major implications: i) the reduction to fundamental units allows sufficient time to unravel the major deformation mechanisms to the atomic level, ii) the recurrent nature of the few fundamental building blocks will allow a transfer of this knowledge to a large number of complex phases, and iii) together, this will enable data mining from the vast and largely unexplored phase space of intermetallics.
Therefore, the key aspect of FUNBLOCKS is to close the existing gap in knowledge and allow us to find promising new phases by elucidating the fundamental relationships between crystal structure and plasticity beyond what we know in simple metals. To identify and quantify the intrinsic mechanical properties of each subunit, state-of-the-art micromechanical testing techniques will be used. Transfer of data and verification of the central hypothesis, that fundamental units govern plasticity in complex crystals, will be achieved via additional alloyed crystals forming ternary variants of the binary structures.
Ultimately, FUNBLOCKS will answer fundamental questions in plasticity, most prominently the interplay of deformation and structure in complex crystals, and thereby support the development of new high performance materials.
During the first half of FunBlock's duration, we have laid the groundwork in terms of experiments and simulations. Experimentally, we have mastered the synthesis of all planned Fe-Ta-Al phases and continue to explore new routes to achieve phase pure Sm-Co castings. En route, intermetallics from both systems have been characterised extensively using scanning electron microscopy including a chemical, orientation and phase analysis. Following on from this work, we have successfully performed nanomechanical testing on a range of samples to determine active slip systems in the SmCo5 phase and the Fe6Ta7 µ-phase at room temperature and have begun to explore further compositions by nanoindentation.
Computationally, we have interrogated the same phases from the Sm-Co and Fe-Ta systems in terms of their elastic constants and have calculated stacking fault energies of different crystalline planes in several relevant intermetallics. We have also explored the fundamental mechanisms of dislocation motion in Laves phases that are isostructural to those synthesised in the experiments as well as the SmCo5 phase. Recently, we have expanded our efforts towards accurate representation of the contained rare earth element by density functional theory in order to provide the best possible reference for the atomistic simulations.
Along the way, we have developed tools for use by other researchers both for experiments using slip trace analysis to identify active slip planes and theoretical investigations into Laves phases for the visualisation and analysis of their crystal structures and their defects from atomistic simulations. We also collaborate closely will other projects and colleagues working on related phases and questions of plasticity in intermetallic crystals.
Computationally, we have interrogated the same phases from the Sm-Co and Fe-Ta systems in terms of their elastic constants and have calculated stacking fault energies of different crystalline planes in several relevant intermetallics. We have also explored the fundamental mechanisms of dislocation motion in Laves phases that are isostructural to those synthesised in the experiments as well as the SmCo5 phase. Recently, we have expanded our efforts towards accurate representation of the contained rare earth element by density functional theory in order to provide the best possible reference for the atomistic simulations.
Along the way, we have developed tools for use by other researchers both for experiments using slip trace analysis to identify active slip planes and theoretical investigations into Laves phases for the visualisation and analysis of their crystal structures and their defects from atomistic simulations. We also collaborate closely will other projects and colleagues working on related phases and questions of plasticity in intermetallic crystals.
Our preliminary results have proved very encouraging in that we could indeed show that the materials we investigate deform by dislocation slip and not, as had been suggested in part, by amorphisation. We could characterise the major active slip systems and directly relate our experimental and computational results. In the near future, we expect to conclude current work that will reveal the strong interplay of the local structure and chemistry of the fundamental building blocks of crystals and the dislocation mechanisms and critical stresses associated with them. By further pursuing this avenue of research, we hope to successfully address our main objective, namely to provide descriptors for plasticity in complex crystals on the basis of the fundamental building blocks selected for FunBlocks.