Texture Evolution and Softening During Discontinuous Dynamic Recrystallization

不连续动态再结晶过程中的织构演变和软化

• 批准号: 1662646
• 负责人: Stephen Niezgoda
• 金额: $ 41.58万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1662646&HistoricalAwards=false
• 关键词: Texture; Evolution; Softening; During; Discontinuous

Metals are enablers of numerous advanced engineering designs that require high strength and toughness, and remain irreplaceable for key components in structural applications in aviation, transportation, power generation, etc. The mechanical properties of engineering metals are closely related to their internal microstructure, which is obtained and optimized through thermal and mechanical processing. However, the processing-microstructure relationship is still poorly understood, which severely limits the prospect of direct one-step microstructure engineering. This award supports an integrated computational and experimental study to establish a quantitative physics-based model that will be used to explore the fundamental mechanisms that control microstructure evolution during hot working. The model will have the ability to assist in the design and optimization of thermomechanical processes for many engineering alloys including nickel-based superalloys for high temperature applications and magnesium-alloys for light structural applications. The PIs are committed to support an undergraduate research program as well as an existing university program that engages undergraduate researchers as mentors who develop K-12 engineering outreach activities under the guidance of K-12 educators.Dynamic recrystallization (DRX) involves the nucleation and growth of new grains during straining at elevated temperatures and plays a critical role in controlling microstructure changes during thermomechanical processing (TMP). Nevertheless, many aspects of DRX remain poorly understood, with the lack of both fundamental knowledge and predictive physics-based models for the evolution of dislocation density, grain structure and texture and the corresponding effects on the macroscopic stress-strain response. This award supports an integrated computational and experimental study that will first establish a full-field DRX model by dynamically coupling a phase-field recrystallization model with a fast Fourier transform crystal plasticity model. Then the model will be used to investigate the following central hypothesis on DRX: The orientation of newly nucleated grains and the degree of subsequent softening are direct consequences of the long-range, inter-granular stress field resulting from plastic anisotropy and the dislocation structure evolution near grain boundaries. In addition to the traditional bulging mechanism, a new DRX nucleation mechanism that selects orientations for easy elastic or plastic deformation will be tested. The computational model established in this project will be directly applicable to many important engineering alloys such as nickel-base superalloys and magnesium-alloys during TMP. The processing-texture-property relationship established in this research will improve the fundamental understanding of the interplay between microstructural and micromechanical fields during DRX and may lead to better optimization of industrial processing.

金属是许多需要高强度和高韧性的先进工程设计的推动者，在航空、交通、发电等结构应用中仍然是不可替代的关键部件。工程金属的力学性能与其内部组织密切相关，内部组织是通过热加工和机械加工获得和优化的。然而，加工与显微组织的关系还不是很清楚，这严重限制了直接一步法微结构工程的前景。该奖项支持一项综合的计算和实验研究，以建立一个基于物理的定量模型，该模型将用于探索控制热加工过程中微结构演变的基本机制。该模型将能够帮助设计和优化许多工程合金的热机械工艺，包括用于高温应用的镍基高温合金和用于轻型结构应用的镁合金。PIS致力于支持一个本科生研究计划和一个现有的大学计划，该计划聘请本科生研究人员作为导师，在K-12教育人员的指导下开展K-12工程推广活动。动态再结晶(DRX)涉及高温应变过程中新晶体的形核和生长，在控制热机械加工(TMP)过程中的组织变化方面发挥着关键作用。然而，DRX的许多方面仍然知之甚少，缺乏基础知识和基于物理的预测模型来描述位错密度、颗粒结构和织构的演化以及对宏观应力-应变响应的相应影响。该奖项支持一项综合的计算和实验研究，该研究将首先通过动态耦合相场再结晶模型和快速傅立叶变换晶体塑性模型来建立全场DRX模型。然后，该模型将被用来研究如下关于DRX的中心假设：新形核的晶粒取向和随后的软化程度是由塑性各向异性引起的长程晶间应力场和晶界附近位错结构演化的直接结果。除了传统的胀形机制外，还将测试一种新的DRX形核机制，该机制可以选择易于弹性或塑性变形的方向。本项目所建立的计算模型将直接适用于镍基高温合金、镁合金等许多重要的工程合金。本研究建立的加工-织构-性能关系将从根本上加深对DRX过程中微结构和微观机械场相互作用的理解，并可能导致更好地优化工业加工。

项目成果

Comparison of full field predictions of crystal plasticity simulations using the Voce and the dislocation density based hardening laws

• DOI: 10.1016/j.ijplas.2021.103099
• 发表时间: 2021-09
• 期刊: International Journal of Plasticity
• 影响因子: 9.8
• 作者: C. Patil;Supriyo Chakraborty;S. Niezgoda

Supersolvus Hot Workability and Dynamic Recrystallization in Wrought Co–Al–W-Base Alloys.

变形钴铝钨基合金的超溶线热加工性和动态再结晶。

• DOI: 10.1007/978-3-030-51834-9_84
• 发表时间: 2020
• 期刊: Superalloys 2020
• 作者: Wertz, K.;Weaver, D.;Wen, D.;Titus, M.S.;Shivpuri, R.;Niezgoda, S.R.;Mills, M.J.;Semiatin, S.L.
• 通讯作者: Semiatin, S.L.

Finite strain phase-field microelasticity theory for modeling microstructural evolution

• DOI: 10.1016/j.actamat.2020.03.033
• 发表时间: 2020-06
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: P. Zhao;T. Low;Yunzhi Wang;S. Niezgoda

Microstructural and micromechanical evolution during dynamic recrystallization

• DOI: 10.1016/j.ijplas.2017.09.009
• 发表时间: 2018
• 期刊: International Journal of Plasticity
• 影响因子: 9.8
• 作者: P. Zhao;Yunzhi Wang;S. Niezgoda