NCJ Number
208573
Journal
Journal of Forensic Sciences Volume: 50 Issue: 1 Dated: January 2005 Pages: 104-111
Date Published
January 2005
Length
8 pages
Annotation
This paper reports on a study that examined whether quantitative information on the size and nature of an explosive blast could be determined by using Orientation Imaging Microscopy (OIM) to analyze the texture of blast-affected metal.
Abstract
Since the pressure of an explosive blast declines by two orders of magnitude if an air gap exists between the explosive and the metal, the most dramatic deformation effects should occur for explosives in contact with the test piece. The purpose of the current study was to determine whether OIM could be used to determine the pressure wave type and amplitude. One thousand eighteen steel and 2,024 aluminum samples were subjected to various explosive blasts designed to simulate a wide range of possible pressure waves. The explosives used were PBX 9404, Comp-C4, Gelmax, and Bullseye. Sample locations were selected to provide a range of pressure values away from the blast in various directions. All samples were examined with an Amray 1845 field emission scanning electron microscope equipped with a TSL orientation imaging system. The data obtained for each set consisted of the images and the quantitative numerical values assigned for a number of different methods of describing the sample's crystallographic texture. This paper displays representative OIM images to provide a general overview of the types of images obtained. Quantitative data are then discussed. The testing found that although suitable patterns could be obtained from the steel samples, the oxide layer present on the surface of the aluminum samples prevented them from being analyzed. OIM findings on the steel sample indicated that damage can be tracked with OIM imaging and that Comp-C4 apparently produces patterns significantly different from the other explosives used. Suggestions are offered for future research study. 3 tables, 7 figures, and 14 references