CMMI-EPSRC: Quantitative Characterization of Mission Critical Microstructures of Engineering Metals with Diffusive Ultrasound

该奖项由NSF工程和物理科学研究理事会牵头机构(ENG-EPSRC)Opportunity提供资金，这是NSF和英国研究与创新(UKRI)的工程和物理科学研究理事会(EPSRC)之间的合作征集活动。它将资助能够可靠保证安全关键金属部件的研究，例如用于航空航天和核电行业的部件，从而促进科学进步，促进国家繁荣和福利。金属零件制造过程中发生的热机械过程导致了决定强度、疲劳寿命、蠕变和耐腐蚀性的颗粒组织。至关重要的是，在生产过程中必须仔细控制这些微结构，并在部件完成后对其进行非破坏性表征。虽然超声波技术是获取材料内部性能的唯一实用手段，但它的工业应用非常有限，因为从这种微结构的角度准确解释超声波信号仍然是一个尚未解决的问题。依赖在精心准备之后对牺牲样品进行破坏性测试的替代技术被认为是不充分的，例如飞机发动机的故障就证明了这一点。该项目将通过提出一种新的方法来解释由于微结构结构和不均匀引起的超声波散射，从而克服这些缺点，潜在地革命性地在整个生产和服务、高温和复杂形状上使用非破坏性、非接触式超声表征。这一能力将支持新的先进制造工艺的发展，其对复杂几何形状的质量控制和保证的关键需求目前仅得到部分满足。与伦敦帝国理工学院博兰博士的合作将提供国际研究交流和博士后科学家培训的机会，以及通过英国无损评估研究中心促进行业推广的途径。这项研究旨在为开发能够对工程金属的关键任务微结构进行体积表征的超声波扩散波场方法做出基础性贡献。它将通过设计和校准实验转换机制和信号处理技术来实现这一目标，以从不同样品几何形状的漫射波场中提取完整的格林张量，并将扩散系数、衰减和散射特性与微结构相关特性联系起来。进一步，我们将把多重散射理论与辐射传输理论结合起来，推导出一个普遍的多重散射理论，以考虑织构和微结构对相干波的影响，并描述非相干波的扩散。这种波扩散的计算模型将根据实验结果进行验证，并用于构建扩散波场与材料微观结构之间定量联系的知识库。最后，将开发一种稳健的反演方法，用于从漫射波场数据中推断关键的微结构属性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded through the NSF Directorate for Engineering - UKRI Engineering and Physical Sciences Research Council Lead Agency (ENG-EPSRC) Opportunity, a collaborative solicitation between NSF and the Engineering and Physical Sciences Research Council (EPSRC) of United Kingdom Research and Innovation (UKRI). It will fund research that enables reliable assurance of safety-critical metal components, for example those used in the aerospace and nuclear power industries, thereby promoting the progress of science, and advancing the national prosperity and welfare. Thermomechanical processes that occur during manufacturing of metal parts result in grain microstructures that dictate strength, fatigue life, and creep and corrosion resistance. It is essential that these microstructures be carefully controlled during production and non-destructively characterized once a component is finished. Although ultrasound technology is the only practical means to access internal material properties, it has seen very limited industrial usage, as accurate interpretation of ultrasonic signals in terms of such microstructure remains an unsolved problem. Alternative techniques that rely on destructive testing of sacrificial samples after elaborate preparation are recognized as inadequate, as evidenced for example by failures of aircraft engines. This project will overcome these shortcomings by advancing a new method of interpreting ultrasonic wave scattering due to microstructural texture and inhomogeneities, potentially revolutionizing the use of non-destructive, contactless, ultrasonic characterization throughout production and in service, at elevated temperatures and on complex shapes. This capability will support the growth of new advanced manufacturing processes, whose vital need of quality control and assurance on complex geometries is currently only partially met. Collaboration with Dr. Bo Lan of Imperial College London will provide opportunities for international research exchange and training of postdoctoral scientists, as well as routes for industry outreach facilitated through the United Kingdom Research Centre in Nondestructive Evaluation.This research aims to make fundamental contributions to the development of an ultrasonic diffuse wave field method that enables volumetric characterization of mission critical microstructure of engineering metals. It will achieve this objective by designing and calibrating experimental transduction mechanisms and signal processing techniques for extracting the full Green’s tensor from the diffuse wave field on different sample geometries, and relating properties of diffusivity, attenuation, and scattering to microstructure-related properties. Further, a general multiple scattering theory will be derived in combination with radiative transfer theory, to account for the effects of texture and microstructures on coherent waves and to describe the incoherent wave diffusion. Computational models of such wave diffusion will be validated against experimental results and used to construct a knowledge database of quantitative linkages between the diffuse wave field and material microstructures. Finally, a robust inversion method will be developed for deducing critical microstructural properties from the diffuse wave field data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.