Team Investigators –
SHAWN A. SAPP, Ph.D.
The Right Intel Solves the Problem
In addition to human and environmental factors, materials (metal, wood, ceramics, plastics, composites, etc.) can contribute, either negatively or positively, to the cause and severity of damages. Engineering, physics, and chemistry are the core of most forensic investigations, but Materials Science is a specialty field that encompasses all of these sciences as separate disciplines dedicated to the understanding of the structure and behavior of various materials. AEI Corporation has the Materials Science expertise to understand interactions between differing materials and environmental conditions, and how these interactions and conditions contribute to the material failures at the heart of an incident.
Failure Analysis and Fractography
AEI Corporation’s investigators work effectively at scenes to determine the origin and cause (O&C) of each incident. Proper processing of a scene includes the careful preservation and extraction of artifacts that are involved (or suspected) in the O&C of the incident. Close examination of these artifacts in the controlled environment of a laboratory, with a process called Failure Analysis, allows us to zero in on the causal factors that led to the incident. Laboratory examinations typically begin with non-destructive documentation and imaging of failed parts and materials, and if necessary, continue into destructive analysis and imaging down to the sub-micron level.
An integral part of Failure Analysis is a technique called “Fractography,” which can be loosely understood as the science of interpreting the features present on fractured surfaces. Every fracture can tell a story of how it began, grew, and finished; whether by overloading due to external stresses, stress from environmental or chemical corrosion, blunt impact damage, improper use of tooling, or slow cyclic fatigue. Each of these failure causes results in a very different set of fracture surface features, and AEI Corporation has the expertise to identify and interpret these features using a variety of quantitative and qualitative analysis techniques.
At AEI Corporation, we have Materials Science expertise in the following areas:
Metal, Corrosion, and Electronics
• Stress corrosion cracking (SCC)
• Ductile failure, creep, and fatigue fractography
• Galvanic, environmental, or biological corrosion
• Plating technology processes and procedures
• Alloy and base metal embrittlement
• Primers, paints, and coatings—selection, compatibility, and failures
• Cathodic corrosion protection
• Electrostatic discharge—diagnosis and mitigation through grounding and bonding
• Arc mapping and identifying direct/indirect lighting strikes
• Electronics, circuits, and PCB failures
• Batteries, ultra-capacitors, and transformers
Ceramics, Glass, and Hardened Metal
• Surface defect identification (grinding, polishing, and finishing)
• Brittle fracture fractography (origin, hackle, Wallner lines, etc.)
• Surface hardening technology processes and procedures (nitriding, ion-embedding, etc.)
• Thermal and chemical tempering/toughening technologies (e.g. Gorilla Glass®)
• High voltage insulator/dielectric breakdown
• Thermal shock or impact damage
Plastics, Rubbers, Adhesives, and Composites
• Environmental stress cracking
• Materials compatibility and selection
• Plasticizer and additive leaching or embrittlement
• Resin chemistry and formulation
• Surfactants, foam, and anti-foam technologies
• Tribology: abrasion, adhesion, cohesion, and erosion
• Tribo-electric charging and discharging
• Seamless heat “welding”
We have expertise in the following analytical methods used in Materials Science and Failure Analysis:
• Metallography, microstructural alloy testing, and alloy standards
• Rockwell, Brinell, and Durometer hardness testing
• Stress-strain measurements (tensile, compressive, shear, yield, etc.)
• Dynamic mechanical analysis (elastic modulus, ductile-to-brittle or glass-transitions, etc.)
• AC and DC electronic testing (impedance, resistance, permittivity, TTR, etc.)
• Electrochemical analysis: voltammetry, Tafel, EIS, and corrosion testing
• Stereo optical microscopy, compound optical microscopy, and digital microscopy
• Optical and digital metrology, particle sizing, profilometry, and 3D scanning and visualization
• Electron Microscopy: SEM, TEM, FE-SEM, and EDS mapping
• Photography and video processing, analysis, and enhancement
• Fracture mechanics, stress-concentration factors, and critical feature size calculation
• Spectroscopy: OES, EDS, WDS, XRF, FTIR, UV-vis-NIR, NMR, etc.
• Specialty chemical analysis: GC-MS, ICP-MS, HPLC, ion chromatography, dielectric fluid, etc.
• Residue analysis and identification: VOCs, gunshot and explosive residues, accelerants, fibers, etc.
• Thermal Testing: TGA/DSC, TC, thermopile, calorimetry (heat flux), and FLIR