Intelligent Sensors for Atomization Processing of Molten Metals and Alloys
ABSTRACT We briefly introduce the principles of atomization processing of molten metals and alloys, discuss potentially applicable instrumentation, and propose opportunities for developing intelligent sensors for monitoring and control of the process. Particle size and velocity are considered the two most important variables to monitor and control the atomization process. Several on-line sensors suitable for atomization of molten metals and alloys are compared: laser light scattering methods using small angle scattering analysis, moderate angle scattering analysis, and doppler analysis, electrical methods using surface ionization and triboelectric charging, and image analysis. The isokinetic sampling probe is introduced as a direct method to sample powders at the desired point in the atomized spray. Prospects and problems of integrating instruments based on these principles into intelligent processing of materials (IPM) scenarios are discussed.
Review on Microstructure Analysis of Metals and Alloys Using Image Analysis Techniques
The metals and alloys find vast application in engineering and domestic sectors. The mechanical properties of the metals and alloys are influenced by their microstructure. Hence the microstructural investigation is very critical. Traditionally the microstructure is studied using optical microscope with suitable metallurgical preparation. The past few decades the computers are applied in the capture and analysis of the optical micrographs. The advent of computer softwares like digital image processing and computer vision technologies are a boon to the analysis of the microstructure. In this paper the literature study of the various developments in the microstructural analysis, is done. The conventional optical microscope is complemented by the use of Scanning Electron Microscope (SEM) and other high end equipments.
Breakup of liquid sheets and jets in a supersonic gas stream
Experimental and analytical results are presented with the objective of denning the mechanism of liquid sheet and j et breakup when subj ected to a supersonic gas stream. Liquid sheets are studied with photomicrographs and high-speed movies of the activity of a liquid layer maintained upon a porous plate test model in a parallel Macli 2.2 freestream. Tests with several different liquids show wave motion, with droplet and ligament shedding across the liquid surface. Numerical results from a liquid surface stability analysis are used to explain these observations. Liquid jets are studied with spark shadowgraphs, high-speed movies and photomicrographs of the normal injection of various liquids into a Mach 2.1 freestream. The results show that the breakup mechanism is characterized by gross jet fracture, as opposed to surface disintegration. 'the degree of breakup at a given streamwise location and jet spread after injection are found to be related to injection diameter and dynamic pressure, and certain liquid properties.