Accession Number : ADA192126
Title : Dynamic Consolidation of Metal Powders.
Descriptive Note : Final rept.,
Corporate Author : LAWRENCE LIVERMORE NATIONAL LAB CA
Personal Author(s) : Gourdin, William H
PDF Url : ADA192126
Report Date : 25 Jan 1988
Pagination or Media Count : 4
Abstract : We have studied the shock wave consolidation of copper, 4330 steel and aluminum+6% silicon powders. We measured the Hugoniots of the unsintered powders using piezoresistive pressure sensors as well as impedance matching techniques and found that they can be well described by available models for pore collapse. An elementary model for the surface heating was developed based on the flux of energy at the interfaces between powder particles during compaction. This model was found to agree quantitatively with observations of localized microstructural modifications in recovered specimens. We found that most of the energy of the compaction shock is deposited at the particle interfaces and that powder particle morphology and specific surface area are important variables. Localized thermal modifications can be either solid state transformations or surface melting and rapid cooling can produce metastable structures. Knowledge of the shock history is essential to the interpretation and control of the consolidated microstructure. We have produced and tested consolidated aluminum+6% silicon that has tensile properties comparable to those of wrought material.
Descriptors : *COMPACTING, *MELTING, *POWDER METALS, COPPER, HEATING, HUGONIOT EQUATIONS, IMPEDANCE MATCHING, INTERFACES, METASTABLE STATE, MICROSTRUCTURE, MODELS, MORPHOLOGY, PIEZOELECTRICITY, PRESSURE TRANSDUCERS, SHOCK WAVES, SOLID STATE PHYSICS, SURFACE TEMPERATURE, TENSILE PROPERTIES, THERMAL PROPERTIES, WROUGHT METALS, SINTERING, ALUMINUM, SILICON, PHASE TRANSFORMATIONS, STAINLESS STEEL
Subject Categories : Metallurgy and Metallography
Distribution Statement : APPROVED FOR PUBLIC RELEASE