Reducing Emissions by Exploiting Field-Induced Martensitic Transformations

通过利用场诱导马氏体相变减少排放

基本信息

批准号：
EP/H004882/1
负责人：
David Dye
金额：
$ 146.78万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FH004882%2F1
关键词：
Reducing Emissions Exploiting Field Induced

项目摘要

The aim of the the fellowship will be to develop the analysis tools to design and use materials that exploit stress- and electromagnetic field-affected phase transformations. This area extends from bainite and martensite in steels to the variant selection problem during the beta->alpha transformation in titanium and zirconium alloys, from omega superelasticity in the beta-Ti alloy GUM metal to NiTi shape memory alloys (SMAs) and ferromagnetic SMAs. In the component context, conventional SMAs rely on a temperature change to provide actuation, which is achieved either passively in response to the environment or by heating / cooling using bleed air, resistance heating or heating filaments. Ferromagnetic SMAs use an electromagnetic field, which allows much faster switching, for example in a pump or to improve flow control. While the crystallography of these transformations is well understood, models are not generally available for the micromechanics that can be incorporated into Finite Element (FE) descriptions of component behaviour used by designers. In addition, whilst these systems are clearly tractable to atomistic approaches, atomistic modeling is still too immature to reliably design new alloys without experimental support; however approaches such as density functional theory (DFT) can enable insight into alloy design approaches to be developed. A subsidiary aim will be to start to bridge the gap to the DFT community. In conventional alloys the problem is often complicated by a diffusional component to the transformation, or nucleation may be the limiting step. However, we have recently shown clearly that applied stress can bias variant selection, leading to the production of mono-variant transformed beta grains in Ti-6246, with consequent effects on properties. The ability to model variant selection in diffusionless transformations, such as in martensite in steels, omega in Ti and Zr, and in (f)SMAs will be a prerequisite to modeling the more complicated problem in Ti-64 and Ti-6246. Industrially, the major goal of the fellowship will be to build a capability to model such transformations and to design alloys exploiting them for use in aerospace, automotive and power applications, with QinetiQ, Rolls-Royce, Timet, Corus and DSTL.

该奖学金的目标是开发分析工具来设计和使用利用受应力和电磁场影响的相变的材料。该领域从钢中的贝氏体和马氏体延伸到钛和锆合金中 β->α 转变过程中的变体选择问题，从 β-Ti 合金 GUM 金属中的 omega 超弹性到 NiTi 形状记忆合金 (SMA) 和铁磁 SMA。在组件环境中，传统 SMA 依靠温度变化来提供驱动，这可以通过被动响应环境或通过使用引气、电阻加热或加热丝进行加热/冷却来实现。铁磁 SMA 使用电磁场，可以实现更快的切换，例如在泵中或改善流量控制。虽然这些转变的晶体学已被很好地理解，但通常无法使用可纳入设计人员使用的组件行为的有限元 (FE) 描述的微观力学模型。此外，虽然这些系统显然易于采用原子方法，但原子建模仍然太不成熟，无法在没有实验支持的情况下可靠地设计新合金；然而，密度泛函理论 (DFT) 等方法可以深入了解待开发的合金设计方法。另一个目标是开始弥合与 DFT 社区的差距。在传统合金中，问题通常因相变的扩散成分而变得复杂，或者成核可能是限制步骤。然而，我们最近清楚地表明，施加的应力会使变体选择产生偏差，导致 Ti-6246 中产生单变体转化的 β 晶粒，从而对性能产生影响。对无扩散转变中的变体选择进行建模的能力，例如钢中的马氏体、Ti 和 Zr 中的 omega 以及 (f)SMA，将是对 Ti-64 和 Ti-6246 中更复杂的问题进行建模的先决条件。在工业上，该奖学金的主要目标将是与 QinetiQ、劳斯莱斯、Timet、Corus 和 DSTL 一起建立模拟此类转变的能力，并设计将其用于航空航天、汽车和电力应用的合金。