Design and mechanical properties of compositionally complex alloys from twinning-induced towards bidirectional transformation-induced plasticity (MULTI-TRIP CCAs)

从孪生诱发塑性到双向相变诱发塑性的成分复杂合金的设计和机械性能（MULTI-TRIP CCA）

• 批准号: 388544551
• 负责人: Dr. Fritz Körmann
• 金额: --
• 依托单位: Max-Planck-Institut für Eisenforschung GmbH (MPIE)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/388544551?language=en
• 关键词: Design; mechanical; properties; compositionally; complex

The transformation induced plasticity (TRIP) effect has been successfully introduced into interstitially alloyed face centered cubic (FCC) CrCoNiMnFe-based HEAs utilizing a combined ab initio-experimental approach. Three quinary HEAs have been selected from ab initio calculations, experimentally prepared and investigated. The atomistic calculations allowed us to interpret the different observed deformation modes and highlight the high efficiency of the developed coupled ab initio-experimental approach developed within the first project for developing mechanically high-performing, low-SFE, interstitially alloyed CCAs. Further opportunities lie in the exploration of thermodynamics and properties of such near-zero SFE HEAs. In these alloys, the matrix could possibly assume both the hexagonal closed packed (HCP) and FCC structure, in adjacent regions of the same bulk microstructure, owing to the energetic equivalence of the coexisting phases. The similarity in phase energy can lead to a bidirectional TRIP effect, in which FCC-structured matrix portions transform under load into HCP regions and vice versa, depending on the local, micromechanical stresses. This effect can lead to an extreme microstructure refinement down to the nanometer regime and enhanced mechanical properties.The project MULTI-TRIP CCAs builds on the successful first project phase and aims at further significantly enhancing the strength-ductility combination of quinary CCAs by introducing the bidirectional TRIP effect into interstitially alloyed CCAs. This will be achieved by combining state-of-the-art ab initio calculations and multiple experimental techniques such as rapid alloy prototyping (RAP), digital image correlation (DIC) assisted tensile testing, electron backscatter diffraction (EBSD), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atom probe tomography (APT). Ab initio calculations will be used to screen a large compositional HEA/CCA phase space for promising low-SFE candidate alloys. Key quantities linking the quantum-mechanical calculations and experiment are, e.g., the generalized SFEs and HCP, FCC, and DHCP phase energies. Non-equiatomic quinary CoCrFeMnNi alloys with near-zero SFEs will be developed by fine-tuning the concentrations including interstitial C, N and H. Each principal element will have a concentration between 5 and 35 at. %, and the content of minor interstitial alloying elements (C, N, H) will be low (less than 1.5 at. %). In relation to the first project phase MULTI-TRIP CCA explores a larger compositional phase space including also variations of Cr and Co. The ab initio simulations will allow us to identify promising alloys, design rules and physical interpretations. The above-mentioned advanced experimental techniques will be utilized to demonstrate the superior mechanical properties of the new materials and reveal the underlying mechanisms via micro- and nanoscale microstructural investigations.

采用从头算和实验相结合的方法，将相变诱发塑性（TRIP）效应成功地引入到非晶合金化的面心立方（FCC）CrCoNiMnFe基HEAs中。三个五元HEAs已选择从头计算，实验制备和研究。原子计算使我们能够解释不同的观察到的变形模式，并突出了高效率的开发耦合从头算实验方法开发的第一个项目中开发的机械高性能，低SFE，合金化的CCA。进一步的机会在于探索这种近零SFE HEAs的热力学和性质。在这些合金中，由于共存相的能量等效性，在相同块体微观结构的相邻区域中，基质可能呈现六方密堆积（HCP）和FCC结构。相能量的相似性可以导致双向TRIP效应，其中FCC结构的基质部分在负载下转化为HCP区域，反之亦然，这取决于局部的微机械应力。MULTI-TRIP CCAs项目是在第一阶段项目成功的基础上，旨在通过将双向TRIP效应引入非晶合金化CCAs中，进一步显著提高五元CCAs的强度-延展性组合。这将通过结合最先进的从头计算和多种实验技术来实现，例如快速合金原型（RAP），数字图像相关（DIC）辅助拉伸测试，电子背散射衍射（EBSD），X射线衍射（XRD），透射电子显微镜（TEM）和原子探针断层扫描（APT）。从头计算将被用来筛选一个大的组成HEA/CCA相空间有前途的低SFE候选合金。连接量子力学计算和实验的关键量是，例如，广义SFE和HCP，FCC和DHCP相能量。通过微调间隙C、N和H的浓度，可以得到具有近零SFE的非等原子五元CoCrFeMnNi合金。每种主要元素的浓度在5至35原子当量之间。%，并且次要间隙合金元素（C、N、H）的含量将较低（小于1.5at. %).相对于第一个项目阶段，MULTI-TRIP CCA探索了一个更大的成分相空间，包括Cr和Co的变化。从头算模拟将使我们能够识别有前途的合金，设计规则和物理解释。上述先进的实验技术将被用来证明新材料的上级机械性能，并通过微观和纳米级微观结构研究揭示潜在的机制。