The Influence of Detonation Velocity on the Microstructure of Materials in Free Explosive Forming

This paper investigates the influence of detonation velocity on the microstructure of materials subjected to free explosive forming. Explosive forming, a high-speed metalworking technique that utilizes shock waves from controlled detonations, enables the formation of complex geometries without the need for expensive tooling or presses. The study focuses on forming spherical components without the use of molds, utilizing segmented designs and various energy transfer media, including water. A physical model of a segmented sphere was created using 3D printing, followed by explosive forming using Poladyn 31ECO plastic explosive. Experimental work involved the fabrication of a six-segment steel sphere, formed and analyzed for microstructural changes using metallographic techniques. Metallographic analysis was conducted on the samples to assess changes in the microstructure. Results indicate that, under the tested conditions with relatively low explosive quantities, only minimal microstructural changes were observed, primarily a ferrite matrix with coagulated pearlite. The findings suggest that higher explosive charges are necessary to induce significant plastic deformation and observable microstructural transformations.