Anisotropic grain noise in eddy current inspection of noncubic polycrystalline metals
نویسندگان
چکیده
This letter discusses the role electrical anisotropy plays in the structural integrity assessment of polycrystalline titanium alloys from the standpoint of fatigue crack detection and the related issue of microstructural noise. In eddy current inspection of noncubic crystallographic classes of polycrystalline metals the electric anisotropy of individual grains produces an inherent microstructural variation or noise that is very similar to the well-known acoustic noise produced by the elastic anisotropy of both cubic and noncubic materials in ultrasonic characterization. The presented results demonstrate that although the electrical grain noise is clearly detrimental in eddy current nondestructive testing for small flaws, it can be also exploited for characterization of the microstructure in noncubic polycrystalline materials such as titanium alloys in the same way acoustic grain noise is used for ultrasonic characterization of the microstructure in different materials. © 1998 American Institute of Physics. @S0003-6951~98!03609-2#
منابع مشابه
Multi-Scale Modeling of Anisotropic Polycrystalline
Polycrystalline microstructure often plays an important role in determining the macroscopic behavior of metals. This work is motivated by the case of a spin-formed shaped charge liner. When these liners are compressed and inverted by detonation of an explosive charge, the resulting jet of material exhibits a distinct rotation. There is no asymmetry at the macroscopic level that would suggest a ...
متن کاملElastic wave propagation and scattering in heterogeneous, anisotropic media: Textured polycrystalline materials
Elastic wave propagation and scattering in heterogeneous, anisotropic media: Textured polycrystalline materials" (1999). Faculty Publications from Nebraska Center for Materials and Nanoscience. Paper 60. The propagation of elastic waves through heterogeneous, anisotropic media is considered. Appropriate ensemble averaging of the elastic wave equation leads to the Dyson equation which governs th...
متن کاملRelation Between Firing Conditions Grain Boundary Structure and Magnetic Properties in Polycrystalline MnZn-Ferrites
The influence of the firing conditions on the nanoscale structure of the grain boundaries and on the magnetic properties of polycrystalline MnZn-ferrites is investigated, on specimens of nearly identical microstructures. High oxygen partial pressures favor accumulation of impurity ions at the triple points. Under appropriate oxygen pressures homogeneous accumulation of impurities along the grai...
متن کاملHomogenization methods for anisotropic linear elastic polycrystals
The elastic properties of uniform polycrystalline materials without defects depend on both the constitutive properties of the constituents and the microstructural characteristics like the distribution of grain orientations and grain shapes. For an overview concerning the homogenization of elastic properties see, e.g., [1]. The elementary bounds by Voigt and Reuss take into account only the volu...
متن کاملA P~enomenological Theory for Plastic Deformation of Polygrystalline Metals*
A consistent phenomenologioal theory is developed for t,he plastic deformation properties of a restricted class of polycrystalline metals. The t,heory introduces the concept of a “hardness state” that can be related to the dislocation “structure” generated in the course of plastic deformation. The conditions t,hat must be satisfied if a plastia equation of state is t,o hold are investigated, an...
متن کامل