Deformation Mechanisms of Gradient Steels with High Strength and Ductility

高强高塑梯度钢的变形机制

• 批准号: 2217727
• 负责人: Xinghang Zhang
• 金额: $ 58.77万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2217727&HistoricalAwards=false
• 关键词: Deformation; Mechanisms; Gradient; Steels; Strength

Gradient metals are designed such that the physical properties change steadily with position. This has many benefits but none more than the ability to achieve enhanced strength and ductility at the same time. There are competing views regarding the mechanisms responsible for this phenomenon, but many of these views have not been validated and reconciled. This award will use a combination of novel in situ mechanical testing and modeling at various length scales to distinguish the various deformation mechanisms in gradient steel microstructures. Structurally gradient steels with high strength and ductility have broad applications in nuclear, petrochemical and automobile industries. The fundamental knowledge derived from this study may be generally applicable for the design of other strong and ductile structural metallic materials. The award will also support an extensive education and outreach plan, including the opportunity for graduate students to work with collaborators at a national laboratory, recruitment of minority undergraduate students as interns, and mentoring of middle and high school students in science fairs.The objective of this grant is to investigate, at a fundamental level, the influence of microstructure gradient on mechanical behavior of steels by integrating severe plastic deformation, in situ micromechanical testing, and crystal plasticity simulations. The goal is to design heterogeneous materials with significantly improved mechanical strength and ductility. The hypothesis is that significant grain coarsening of the elongated grain morphology arises from dynamic recrystallization and/or stress-driven grain boundary migration, and the switching between the two mechanisms should be temperature dependent. A further hypothesis is that the suppression of localized shear softening under the combined influence of deformation mechanisms and gradient microstructure evolution leads to increased strength and ductility. To test these hypotheses, a dislocation plasticity based theoretical framework combining plastic deformation, dynamic recrystallization, and stress-driven grain boundary migration will be developed to study gradient microstructures. The modeling will complement the investigation of the fundamental deformation mechanisms by in situ tension microscopy studies at various temperatures and length scales.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.

梯度金属的设计使得物理特性随着位置的变化而稳定变化。这有很多好处，但无非是能够同时提高强度和延展性。关于造成这种现象的机制存在相互竞争的观点，但其中许多观点尚未得到验证和协调。该奖项将结合使用新颖的原位机械测试和不同长度尺度的建模来区分梯度钢微观结构中的各种变形机制。具有高强度和高延展性的结构梯度钢在核工业、石化工业和汽车工业中有着广泛的应用。从这项研究中获得的基础知识可能普遍适用于其他坚固且延展的结构金属材料的设计。该奖项还将支持广泛的教育和推广计划，包括为研究生提供与国家实验室合作者合作的机会、招募少数族裔本科生作为实习生，以及在科学博览会上指导初高中生。该资助旨在通过整合剧烈塑性变形、原位微观机械测试和晶体塑性模拟，从根本上研究微观结构梯度对钢机械行为的影响。目标是设计机械强度和延展性显着提高的异质材料。假设是，拉长晶粒形态的显着晶粒粗化是由动态再结晶和/或应力驱动的晶界迁移引起的，并且两种机制之间的切换应该与温度相关。进一步的假设是，在变形机制和梯度微观结构演化的综合影响下抑制局部剪切软化会导致强度和延展性增加。为了检验这些假设，将开发一个基于位错塑性的理论框架，结合塑性变形、动态再结晶和应力驱动的晶界迁移来研究梯度微观结构。该模型将补充在不同温度和长度尺度下通过原位张力显微镜研究对基本变形机制的研究。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Gradient nanostructured steel with superior tensile plasticity

具有优异拉伸塑性的梯度纳米结构钢

• DOI: 10.1126/sciadv.add9780
• 发表时间: 2023-06-02
• 期刊: Science Advances
• 影响因子: 13.6
• 作者: Z. Shang;Tianyi Sun;Jie Ding;N. A. Richter;N. Heckman;B. White;B. Boyce;K. Hattar;Haiyan Wang
• 通讯作者: Haiyan Wang