GOALI: Nanoparticle Metrics for Computational Materials Mechanics

计算材料力学的纳米粒子度量这个目标程序具有直接评估测量和计算亚微米长度尺度的科学目标。此外，它的工程目标是将其应用于改进的材料工艺，以保护和制造磁记录系统。在科学上，我们正在利用纳米压痕、原子力显微镜和透射电子显微镜测量20至200纳米范围内无缺陷纳米球的机械响应。在相同的边界条件下，利用修正的嵌入原子间势在最小尺度上与较大尺度上的离散位错动力学相结合，对相同数目原子的直接评价进行了评价。用于评估与梯度塑性、体积与表面比和过量表面应力相关的长度尺度的参数包括位错成像、应变硬化措施和表面改性。根据工程目标，将寻求利用原子层沉积（ALD）修饰纳米球表面的薄膜平面化的改进材料工艺。目前正在研究的用于磁记录磁头的纳米级保护的ALD工艺将应用于磁头介质，其目标是提高局部摩擦和磨损性能的算法。主要InvestigatorW.W。Gerberich，明尼苏达大学首席研究员，理学学士。卡特，明尼苏达大学。科廷和A. needleman布朗大学，Provi

Nanoparticle Metrics for Computation Materials MechanicsABSTRACT This GOALI program has the scientific goal of directly evaluating measured and computational submicron length scales. Additionally, it has the engineering goal of applying this to improved materials processes for protecting and manufacturing magnetic recording systems. Scientifically, we are measuring the mechanical response of defect-free nanospheres in the 20 to 200 nm range utilizing nanoindentation, atomic force microscopy, and transmission electron microscopy. Direct evaluation of the identical number of atoms with the identical boundary conditions are being evaluated using modified embedded atom interatomic potentials at the smallest scales coupled with discretized dislocation dynamics at the larger scale. Parameters to evaluate length scales associated with gradient plasticity, volume to surface ratios, and excess surface stress included dislocation imaging, strain hardening measures, and surface modification. Regarding the engineering goals, improved materials processes for planarization of thin films utilizing nanospheres surface-modified by atomic layer deposition (ALD) will be sought. This same ALD process, as currently being investigated for nanometer level protection of heads for magnetic recording will be applied to head media with algorithms for improved performance against localized friction and wear as a goal.Principal InvestigatorW.W. Gerberich, University of MinnesotaCo-Principal InvestigatorsC.B. Carter, University of MinnesotaW.A. Curtin and A. NeedlemanBrown University, Provi