GOALI: Nanoparticle Metrics for Computational Materials Mechanics

计算材料力学的纳米粒子计数器摘要这个GOALI计划的科学目标是直接评估测量和计算亚微米长度尺度。 此外，它的工程目标是将其应用于保护和制造磁记录系统的改进材料工艺。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 nm范围内无缺陷纳米球的机械响应。 直接评估相同数量的原子与相同的边界条件正在评估使用修改后的嵌入式原子间的潜力，在最小的尺度，再加上离散位错动力学在较大的规模。 参数，以评估与梯度塑性，体积表面比，和多余的表面应力的长度尺度包括位错成像，应变硬化措施，和表面改性。 关于工程目标，将寻求用于利用通过原子层沉积（ALD）表面改性的纳米球来平坦化薄膜的改进的材料工艺。 这种相同的ALD工艺，如目前正在研究的纳米级保护磁记录磁头的工艺，将应用于磁头介质，其目标是改善局部摩擦和磨损的性能。Gerberich，明尼苏达大学联合首席研究员C.B.卡特，明尼苏达大学W.A.科廷和A. University of Pennsylvania

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