Characterization of anisotropic materials with the Laser-Ultrasonic technique using the “in plane” and the “out of plane” measurements of the sample surface displacement

2000 ◽  
Author(s):  
Christophe Bescond
Keyword(s):  
Surface Displacement ◽  
Sample Surface ◽  
Anisotropic Materials ◽  
Ultrasonic Technique ◽  
Laser Ultrasonic ◽  
Out Of Plane

Identification of Critical Surface Displacement Parameters for Characterization of Subsurface Flaws

2002 ◽  
Author(s):  
Paul D. Herrington ◽  
Paul J. Schilling ◽  
Melody A. Verges ◽  
Prashanth K. Durgam
Keyword(s):  
Plane Surface ◽  
Surface Displacement ◽  
Homogeneous Material ◽  
Critical Surface ◽  
Near Surface ◽  
Surface Displacements ◽  
Measuring Surface ◽  
Out Of Plane ◽  
Subsurface Geometry

Several NDE methods provide accurate techniques for measuring surface displacements. While these techniques have been successful in identification of near-surface embedded flaws, they generally offer little in terms of characterization of the flaws. The ability to characterize embedded flaws from measurements of surface displacements would offer substantial benefits, especially in terms of remaining life predictions. This paper focuses on the identification of critical out-of-plane surface displacement parameters, and assessment of the potential to characterize subsurface flaw geometry based on these parameters. Finite element models of a homogeneous material have been created that vary the embedded flaw size and edge distance. The results suggest that there is potential to characterize the subsurface geometry from the surface displacement parameters.

scholarly journals Evaluation of Multiple Reflections in the Characterization of Anisotropic Materials by Through Transmission Ultrasonic Technique

2015 ◽  
Vol 70 ◽  
pp. 402-405
Author(s):  
N. Pérez ◽  
F. Buiochi ◽  
D. Yamashita ◽  
M.A. Andrade ◽  
J.C. Adamowski
Keyword(s):  
Anisotropic Materials ◽  
Ultrasonic Technique ◽  
Multiple Reflections

Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 166-167
Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook
Keyword(s):  
Analytical Techniques ◽  
Sample Surface ◽  
Ion Milling ◽  
Cross Sectional ◽  
Reliable Technique ◽  
Near Surface ◽  
Transmission Electron ◽  
Thin Region ◽  
Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

Physical Ultrasonics of Composites

2011 ◽  
Author(s):  
Dale Chimenti ◽  
Stanislav Rokhlin ◽  
Peter Nagy
Keyword(s):  
Composite Laminates ◽  
Stiffness Matrix ◽  
Composite Plates ◽  
Anisotropic Media ◽  
Anisotropic Materials ◽  
Ultrasonic Waves ◽  
Laminated Plates ◽  
Structure Characteristic ◽  
Major Advance

Physical Ultrasonics of Composites is a rigorous introduction to the characterization of composite materials by means of ultrasonic waves. Composites are treated here not simply as uniform media, but as inhomogeneous layered anisotropic media with internal structure characteristic of composite laminates. The objective here is to concentrate on exposing the singular behavior of ultrasonic waves as they interact with layered, anisotropic materials, materials which incorporate those structural elements typical of composite laminates. This book provides a synergistic description of both modeling and experimental methods in addressing wave propagation phenomena and composite property measurements. After a brief review of basic composite mechanics, a thorough treatment of ultrasonics in anisotropic media is presented, along with composite characterization methods. The interaction of ultrasonic waves at interfaces of anisotropic materials is discussed, as are guided waves in composite plates and rods. Waves in layered media are developed from the standpoint of the "Stiffness Matrix", a major advance over the conventional, potentially unstable Transfer Matrix approach. Laminated plates are treated both with the stiffness matrix and using Floquet analysis. The important influence on the received electronic signals in ultrasonic materials characterization from transducer geometry and placement are carefully exposed in a dedicated chapter. Ultrasonic wave interactions are especially susceptible to such influences because ultrasonic transducers are seldom more than a dozen or so wavelengths in diameter. The book ends with a chapter devoted to the emerging field of air-coupled ultrasonics. This new technology has come of age with the development of purpose-built transducers and electronics and is finding ever wider applications, particularly in the characterization of composite laminates.

Electrical Characterization of InAs/(GaIn)Sb Infrared Superlattice Photodiodes for the 8 to 12νm Range

1999 ◽  
Vol 607 ◽  
Author(s):  
L. Bürkle ◽  
F. Fuchs ◽  
R. Kiefer ◽  
W. Pletschen ◽  
R. E. Sah ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Cutoff Wavelength ◽  
Saturation Current ◽  
Diffusion Limited ◽  
Saturation Current Density ◽  
Out Of Plane ◽  
Reverse Saturation Current ◽  
The Magnetic Field ◽  
Diode Current

AbstractInAs/(GaIn)Sb superlattice photodiodes with a cutoff wavelength of 8.711μm show adynamic impedance of R0A= 1.5 kωcm2at 77 K and a responsivity of 2 A/W, corresponding to a detectivity of D*= 1 x 1012 cmv√Hz/W. Diffusion limited performance is observed above 100 K. At lower temperatures the diodesare limited by generation-recombination currents. An analysis of the influence of different diode sidewall passivations on the surface contribution to the diode leakage current is presented. The out-of-plane electron mobility as well as the relative contributions of the electron and hole diffusion currents to the diode current were determined by a measurement of the magnetic field dependence of the reverse saturation current density of the diodes

The study of ultrasonic longitudinal velocities for nanostructured NiAl alloys by laser ultrasonic technique

1998 ◽  
Vol 105 (9) ◽  
pp. 601-604 ◽  
Author(s):  
Yinglei Du ◽  
Baimei Wu ◽  
Xiaorong Zhang ◽  
Xiaoyin Qin
Keyword(s):  
Ultrasonic Technique ◽  
Laser Ultrasonic
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