Directional Recrystallization Processing

定向再结晶加工

• 批准号: 9976509
• 负责人: Ian Baker
• 金额: $ 31.94万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9976509&HistoricalAwards=false
• 关键词: Directional; Recrystallization; Processing

A fundamental study of directional recrystallization processing will be performed with the goal of understanding how key microstructural parameters, principally the interparticle spacing and grain size, interact with the processing conditions (rate of hot zone movement and temperature) to control the microstructure. The study covers both primary recrystallization and grain growth. Initial work is on model systems of copper (single crystals and polycrystals) containing fine hard particles introduced by internal oxidation. For recrystallization, a key question is whether a particle-containing alloy should show accelerated recrystallization or retarded recrystallization (compared to unalloyed copper) in order to be amenable to directional recrystallization processing into a single crystal or columnar-grained structure. For grain growth, determining the role of particle coarsening is key to understanding how elongated grains or single crystals can be produced. The work will involve a close coupling of experiments with computational microstructural simulation. With this fundamental understanding of directional recrystallization, modeling can then be used to guide directional recrystallization of commercially-useful aerospace materials. Thus, the project will also apply the fundamental understanding and modeling expertise developed to directional recrystallization of a nickel-based superalloy. A predictive capability for materials processing is sought regarding what volume fraction, size or spacing of particles should a material include to make it amenable to directional recrystallization. In addition, the state-of-the-art of microstructural simulation will have been advanced.

将进行定向再结晶工艺的基础研究，目的是了解关键的微观组织参数，主要是颗粒间距和晶粒度，如何与工艺条件(热区移动速度和温度)相互作用来控制组织。研究内容包括初次再结晶和晶粒长大两个方面。最初的工作是关于铜(单晶和多晶)的模型系统，其中包含通过内部氧化引入的细小的硬颗粒。对于再结晶，一个关键的问题是，含有颗粒的合金应该表现出加速再结晶还是延迟再结晶(与非合金铜相比)，以便能够进行定向再结晶加工成单晶或柱状组织。对于颗粒生长，确定颗粒粗化的作用是理解细长颗粒或单晶是如何产生的关键。这项工作将包括实验和计算微结构模拟的紧密结合。有了对定向再结晶的基本了解，建模就可以用来指导商业上有用的航空航天材料的定向再结晶。因此，该项目还将应用开发的对镍基高温合金定向再结晶的基本理解和建模专业知识。寻求一种材料加工的预测能力，即一种材料应该包括什么体积分数、大小或颗粒间距，以使其易于定向再结晶。此外，还将推进微观组织模拟的最新进展。