Forensic Metallurgy

Metallurgical engineering involves the study, innovation, design, implementation, and improvement of processes that transform mineral resources and metals into useful products that improve the quality of our lives (University of Utah Department of Metallurgical Engineering 2005). Metals provide the foundation for our modern way of life. Forensic metallurgy is the court-certified failure analyses of machinery, tools, vehicles, boats, airplanes, furniture, structures, buildings, plumbing involving metals, glass, and plastics due to design, manufacturing, and utilization. This analysis is not limited to metals and can be applied to glass, ceramic, plastic, and rubber materials because there is little variety in the techniques used to analyze these materials.

A forensic metallurgist studies every component of a system in order to determine the cause of the failure and the recommended solution for the problem. They determine the molecular structure, the chemical composition, and the environmental conditions surrounding the system, all of which are factors that could affect its strength. Forensic metallurgists are often called to determine failures in small systems (such as industrial accidents) or large systems (such as military equipment and technology).

Metallurgical techniques are seldom reported as being used in forensic science investigations because most findings rely only on visual and chemical examinations. For example, a forensic metallurgist may study the configuration of cracks in a metal surface in order to determine the length of time over which the crack formed and the actual cause of the damage. Metallurgists can also use solutions and acids to isolate the components that make up a metal structure, and therefore determine if the alloy is conforming to established standards for construction. Often, a special type of compound metallographic microscope is used to compare two samples or specimens. This type of scanning electron microscope identifies miniscule defects in metal surfaces and helps determine the crystal grain boundaries in metal alloys.

The information required to determine a link between different pieces of metal is obtained from an examination of the metal's microstructure, which reflects its thermo-mechanical history. This kind of information is specific and cannot be gathered by applying typical techniques, such as chemical analysis. Metallurgical techniques, partnered with other scientific methods, can be successfully employed in a forensic science context (Rittel 1987).

Department of Metallurgical Engineering. 2005. “Metallurgical Engineering”. University of Utah. http://www.metallurgy.utah.edu.

Petesch, C. 2008. “Book by metallurgists blames rivets for Titanic tragedy”. USA Today.
http://www.usatoday.com/news/world/2008-04-18-1804035801_x.htm.

Rittel, D and G. Faingold. 1987. On the Application of Metallurgical Techniques to Forensic Sciences. ASTM International. http://www.astm.org/DIGITAL_LIBRARY/JOURNALS/FORENSIC/PAGES/JFS12452J.htm.

Wald, M. 1994. “March 20-26: Seeking Clues in New Jersey; The Day of the Metallurgist: Bits of Shattered Pipeline Are Gathered for Evidence”. The New York Times. http://www.nytimes.com/1994/03/27/weekinreview/march-20-26-seeking-clues-new-jersey-day-metallurgist-bits-shattered-pipeline.html.