High-Authority Two-Way Surface Form Memory

高权限双向表层内存

• 批准号: 0900127
• 负责人: David Grummon
• 金额: $ 27.99万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0900127&HistoricalAwards=false
• 关键词: Authority; Two; Way; Surface; Form

A new surface engineering technique has been found that will extend the reach of shape memory alloys to new application areas not previously contemplated for these remarkable materials. We have discovered a technique whereby a metallic surface can be made to undergo a thermally-driven transition between an optical flat (when cool), to a highly non-planar surface on warming. This project will demonstrate that Surface Form Memory (SFM) can operate with the high energy density normally associated with shape-memory (106 J-m-3). If so, such ?high-authority? SFM would enable a variety of novel applications, from variable friction surfaces, to MEMS devices and nano-scale assembly tools. The method we use to obtain SFM involves spherical or cylindrical indentation followed by surface planarization. This indent-planarization technique relies on the discovery that a spherical indent made in martensitic NiTi induces a pronounced shape-memory training effect, leading to two-way shape memory (TWSME). This causes shape-strains to occur cyclically on both heating and cooling. This cyclic depth change is converted to a much more radical change in surface form by the planarization step, in which the surface is carefully ground just enough to render the initial indent invisible. What had been a simple change in indent depth is thereby converted to a transition from a flat surface to one exhibiting a pronounced protrusion. We will explore low-cost methods for producing wide-area surface treatments, and evaluate ideas for the fabrication of tribodynamic surfaces and other components using indentation-planarization methods. In particular, we propose a proof-of-concept demonstration of surfaces capable of very large thermally driven changes in friction coefficient.

一种新的表面工程技术已经被发现，这将扩大形状记忆合金的范围到新的应用领域，以前没有考虑这些显着的材料。 我们已经发现了一种技术，通过这种技术，可以使金属表面在光学平面（当冷却时）与加热时的高度非平面表面之间经历热驱动转变。 该项目将证明表面形状记忆（SFM）可以在通常与形状记忆（106 J-m-3）相关的高能量密度下工作。 如果是这样，是什么？高层SFM将使各种新的应用，从可变摩擦表面，到MEMS器件和纳米级组装工具。 我们用来获得SFM的方法包括球形或圆柱形压痕，然后进行表面平坦化。 这种压痕平面化技术依赖于发现在马氏体NiTi中制成的球形微球诱导显著的形状记忆训练效应，从而导致双向形状记忆（TWSME）。 这导致形状应变在加热和冷却时周期性地发生。 这种周期性的深度变化通过平面化步骤转化为表面形式的更根本的变化，在平面化步骤中，表面被仔细地研磨到足以使初始的粗糙度不可见。 因此，从平坦表面到突出表面的过渡转变成了简单的凹陷深度变化。 我们将探索生产大面积表面处理的低成本方法，并评估使用压痕平面化方法制造摩擦动力学表面和其他组件的想法。 特别是，我们提出了一个概念验证的示范表面能够非常大的热驱动的摩擦系数的变化。