共查询到18条相似文献,搜索用时 171 毫秒
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超声检测技术与原子力显微技术相结合,构成原子力声显微镜(AFAM),能够实现样品内部纳米结构的测量,并分析如局域弹性模量、刚度等力学性能.本文在传统的原子力显微镜(AFM)的基础上初步构建了AFAM,利用AFM轻敲模式下的微悬臂梁振动激励信号来驱动样品背面的压电超声换能器,并利用轻敲模式控制系统中的锁相环检测经过样品后由探针收集的振动信号,形成振幅及相位图像.这种AFAM方法不需外接信号发生器、锁相放大器及相关控制电路,从而避免AFM内、外部的仪器及控制电路的不同步而引起的AFAM振幅/相位与形貌图像间的偏移.此外,还分析了形貌结构对AFAM振幅图像的影响,为进一步研究AFAM亚表面成像奠定了基础. 相似文献
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原子力显微镜的发展与表面成象技术 总被引:7,自引:2,他引:5
原子力显微镜(AFM)因其具有超高三维分辨,非接触无损成像,显微倍率连续可调等特点,被誉为是目前国际显微宾重大在和现代表面分析技术的革命性能,通过采用AFM对材料的表面实时扫描成象,获得更为真实而丰富三维图像信息,其在材料的表面科学研究领域中将人 应用前景。 相似文献
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1 引 言 原子力显微镜 (简记为 AFM)是利用其微悬臂梁的机械振动响应于力敏探针和实验样品表面之间的相互作用力来成像的 ,由于具有原子和分子级的分辨率 ,已成为表面成像及材料微结构研究的新工具 ,在科学技术的各种领域获得了广泛的应用 [1-2 ] 。有几种不同模式的 AFM相继被开发使用。在 AFM的接触模工作中 ,其力敏探针始终保持同样品表面相接触 ,力敏探针和样品之间的相互作用力被微悬臂梁位移产生的弹性力所平衡 ,这种接触模式有极高的分辨率 ,但力敏探针上存在横向力 ,对实验样品有较大的损伤 ;在 AFM的非接触模工作中 ,力… 相似文献
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扫描Kelvin探针力显微镜(SKPFM)是在原子力显微镜(AFM)的基础上应用扫描Kelvin探针(SKP)技术开发的检测表征手段,它能够在获取材料表面纳米级分辨率形貌的同时,原位得到样品表面高分辨率的接触电势差分布图,为揭示腐蚀反应机理提供了崭新的思路,近年来发展迅速。本文介绍了SKPFM两种工作模式的基本原理,总结了SKPFM在应用中的问题,并讨论了SKPFM和传统扫描Kelvin探针技术(SKP)的优缺点,重点综述了SKPFM在腐蚀科学研究中的应用,最后展望了SKPFM的发展方向与应用前景。 相似文献
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一种用于微米/纳米硬度测试的具有纳米分辨率的压痕成像系统 总被引:1,自引:0,他引:1
与包括原子力显微镜在内的其他压痕形貌测量方法相比,光学显微镜以其非接触、大测量范围及较快的测量速度等优点在硬度测试中应用广泛,但包括共焦显微镜在内的常规显微镜其分辨率,特别是纵向分辨率,一直不能满足要求.为此开发了一种沿光轴方向的具有纳米分辨率的压痕成像系统.该系统基于层析全场显微术,即在常规光学显微镜的基础上引入结构光照明.应用移相方法得到样品的三维形貌.成像系统样机的测量结果表明,系统的纵向分辨率可达2nm,可以高精度地实现压痕的三维形貌测量,并量化揭示纳米压痕测试中常见的“坟起(pile-up)”及“沉入(sink-in)”现象.该系统有助于进一步研究显微及纳米硬度计量方法并降低计量的不确定度. 相似文献
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D.C. Hurley M. Kopycinska‐Müller A.B. Kos R.H. Geiss 《Advanced Engineering Materials》2005,7(8):713-718
We are developing metrology for rapid, quantitative assessment of elastic properties with nanoscale spatial resolution. Atomic force acoustic microscopy (AFAM) methods enable measurements of modulus at either a single point or as a map of local property variations. The information obtained furthers our understanding of nanopatterned surfaces, thin films, and nanoscale structures. 相似文献
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Balogun O Cole GD Huber R Chinn D Murray TW Spicer JB 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(1):226-233
Scanning acoustic microscopy techniques operating at frequencies in the gigahertz range are suitable for the elastic characterization and interior imaging of solid media with micrometer-scale spatial resolution. Acoustic wave propagation at these frequencies is strongly limited by energy losses, particularly from attenuation in the coupling media used to transmit ultrasound to a specimen, leading to a decrease in the depth in a specimen that can be interrogated. In this work, a laser-based acoustic microscopy technique is presented that uses a pulsed laser source for the generation of broadband acoustic waves and an optical interferometer for detection. The use of a 900-ps microchip pulsed laser facilitates the generation of acoustic waves with frequencies extending up to 1 GHz which allows for the resolution of micrometer-scale features in a specimen. Furthermore, the combination of optical generation and detection approaches eliminates the use of an ultrasonic coupling medium, and allows for elastic characterization and interior imaging at penetration depths on the order of several hundred micrometers. Experimental results illustrating the use of the laser-based acoustic microscopy technique for imaging micrometer-scale subsurface geometrical features in a 70-μm-thick single-crystal silicon wafer with a (100) orientation are presented. 相似文献
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High-resolution ultrasonic methods are briefly reviewed. Special attention is paid to the principles underlying acoustic microscopy,
since exactly they provide the high resolution necessary for modern technologies. Examples of acoustic images of fullerite
ceramics, metals, and carbon materials are given. 相似文献
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The fiber and matrix interphase is believed to control the fundamental load-transfer process and thereby bulk mechanical properties of composites. Carbon fiber reinforced composite properties have been qualitatively shown affected by moisture based degradation, however, quantitative characterization of the nanomechanical properties as a function of exposure time is still unknown. Here, quantitative measurement of the degraded epoxy matrix properties has been performed, taking advantage of the high scanning resolution of atomic force acoustic microscopy (AFAM). Composite samples were exposed to accelerated degradation and characterized using AFAM, showing a variation in elastic modulus of the matrix as a function of exposure. 相似文献
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Wagner H Bedorf D Küchemann S Schwabe M Zhang B Arnold W Samwer K 《Nature materials》2011,10(6):439-442
The nature of non-crystalline materials causes the local potential energy of a cluster of atoms or molecules to vary significantly in space. Different configurations of an ensemble of atoms in a metallic glass lead therefore to a distribution of elastic constants which also changes in space. This is totally different to their crystalline counterparts, where a long-range order exists in space and therefore a much more unified elastic modulus is expected. Using atomic force acoustic microscopy, we present data which show that the local so-called indentation modulus M indeed exhibits a wide distribution on a scale below 10 nm in amorphous PdCuSi, with ΔM/M≈30%. About 10(4) atoms are probed in an individual measurement. Crystallized PdCuSi shows a variation that is 10-30 times smaller and which is determined by the resolution of the microscope and by the polycrystalline structure of the material. 相似文献
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Atomic force microscopy (AFM) is increasingly being used as a nanoindentation tool to measure local elastic properties of
surfaces. In this article, a method based on AFM in force volume (force curve mapping) mode is employed to measure the elastic
modulus distribution at the interface of a glass flake-reinforced polypropylene sample and at a lead-free Cu–solder joint.
Indentation arrays are performed using a diamond AFM tip. The processing of experimental AFM indentation data is automated
by customized software that can analyse and calibrate multiple force curves. The analysis algorithm corrects the obtained
force curves by selecting the contact point, discarding the non-contact region and subtracting the cantilever deflection from
the measured force curve in order to obtain true indentation curves. A Hertzian model is then applied to the resulting AFM
indentation data. Reference materials are used to estimate the tip radius needed to extract the elastic modulus values. With
the proposed AFM measurement method, we are able to obtain high-resolution maps showing elastic modulus variations around
a composite interface and a Cu–solder joint. No distinct interphase region is detected in the composite case, whereas a separate
intermetallic layer (1–2 μm thick) of much higher Young’s modulus (~131 GPa) than Cu and solder material is identified in
the Cu–solder joint. Elastic modulus results obtained for the Cu (~72 GPa), solder (~50 GPa) and glass (~65 GPa) materials
are comparable to the results obtained by instrumented indentation [~73, ~46 and ~61 GPa], which accentuates the potential
of this method for applications requiring high lateral resolution. 相似文献
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Palmeri ML McAleavey SA Fong KL Trahey GE Nightingale KR 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(11):2065-2079
Acoustic radiation force impulse imaging has been used clinically to study the dynamic response of lesions relative to their background material to focused, impulsive acoustic radiation force excitations through the generation of dynamic displacement field images. Dynamic displacement data are typically displayed as a set of parametric images, including displacement immediately after excitation, maximum displacement, time to peak displacement, and recovery time from peak displacement. To date, however, no definitive trends have been established between these parametric images and the tissues' mechanical properties. This work demonstrates that displacement magnitude, time to peak displacement, and recovery time are all inversely related to the Young's modulus in homogeneous elastic media. Experimentally, pulse repetition frequency during displacement tracking limits stiffness resolution using the time to peak displacement parameter. The excitation pulse duration also impacts the time to peak parameter, with longer pulses reducing the inertial effects present during impulsive excitations. Material density affects tissue dynamics, but is not expected to play a significant role in biological tissues. The presence of an elastic spherical inclusion in the imaged medium significantly alters the tissue dynamics in response to impulsive, focused acoustic radiation force excitations. Times to peak displacement for excitations within and outside an elastic inclusion are still indicative of local material stiffness; however, recovery times are altered due to the reflection and transmission of shear waves at the inclusion boundaries. These shear wave interactions cause stiffer inclusions to appear to be displaced longer than the more compliant background material. The magnitude of shear waves reflected at elastic lesion boundaries is dependent on the stiffness contrast between the inclusion and the background material, and the stiffness and size of the inclusion dictate when shear wave reflections within the lesion will interfere with one another. Jitter and bias associated with the ultrasonic displacement tracking also impact the estimation of a tissue's dynamic response to acoustic radiation force excitation. 相似文献
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Cheng B Chang T 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(3):627-635
This work deals with improving the resolution of ultrasonic ranging systems by means of preshaping the transmitter drive signals to achieve low transient acoustic pulses. As ultrasonic transducers are operated at a relatively high nominal frequency and quality factor, feedforward strategy is among the most efficient means to generate the low transient acoustic pulses. In this work, a digital signal processor and a field programmable gate array synthesize the transmitter drive signal to emit low transient pulses which are then applied to the detection of surface features. Both simulation and experiment results confirm an improved spatial detection resolution due to the lower acoustic transient interference. The drive signal synthesis process is also simpler than the conventional modulation method and should result in lower cost of implementation. 相似文献