Academic Credentials
  • Ph.D., Materials Science and Engineering, Colorado State University, 2022
  • B.S., Materials Engineering, Iowa State University, 2017
Licenses & Certifications
  • American Welding Society Certified Welding Inspector (CWI)
  • Professional Engineer Metallurgical and Materials (CA)
  • Red Cross - CPR/AED Certificate
Professional Affiliations
  • ASTM International
  • • Voting Member, Committee F42 – Additive Manufacturing Technologies
  • • Member, Committee F04 – Medical and Surgical Materials and Devices
  • American Welding Society (AWS)

Alexander Preston, Ph.D., P.E., CWI, is a senior engineer in Exponent's Metallurgical & Corrosion Engineering practice. He has conducted numerous investigations in failure analysis, welding metallurgy, tribology, and advanced materials processing, and he has provided technical support in domestic and international litigation proceedings. He advises industrial clients and legal counsel on root-cause investigations, material degradation, and manufacturing quality, specializing in weld failure analysis, wear materials, and additive manufacturing. 

Welding Metallurgy & Failure Analysis

Dr. Preston conducts root-cause failure analyses of welds and welded components across industrial, energy, and consumer product applications. His investigations address weld discontinuities, heat-affected zone (HAZ) degradation, residual stress effects, and in-service cracking mechanisms including stress corrosion cracking and fatigue. As a Certified Welding Inspector (CWI), he evaluates weld procedures, inspection records, and compliance with applicable codes and standards including AWS D1.1, ASME BPVC Section IX, and ASME B31.3.

Bearing Failure & Tribology

Dr. Preston supports clients facing premature bearing failures, surface wear, and tribological degradation in rotating machinery and industrial equipment. His analyses integrate metallographic examination, scanning electron microscopy (SEM), and surface profilometry to characterize wear mechanisms — including adhesive wear, abrasive wear, fretting, and rolling contact fatigue — and to distinguish manufacturing defects from in-service damage. This work informs maintenance strategies, design improvements, and liability assessments for manufacturers, operators, and insurers.

Pressure Vessel & Pipeline Failures

Dr. Preston investigates failures in pressure vessels, boiler piping, pipelines, and industrial process equipment, addressing mechanisms such as corrosion, fatigue, hydrogen embrittlement, and overload fracture. His experience includes gas lines, boiler piping systems, and industrial driers, with analysis methods encompassing metallography, mechanical testing, and finite element modeling (FEM). He advises clients on fitness-for-service assessments, regulatory compliance, and failure prevention strategies relevant to ASME and API standards, technical basis for liability and remediation decisions.

Utility Infrastructure & Electrical Components

Dr. Preston investigates failures in utility infrastructure and electrical components, including overhead conductors, printed circuit boards, and solar junction boxes. His work addresses degradation mechanisms such as corrosion, thermal cycling fatigue, and electrical arcing and draws on materials characterization techniques including differential scanning calorimetry (DSC), UV aging analysis, and electron microscopy. He supports electric utilities, insurers, and legal counsel in understanding the root causes of infrastructure failures and the technical basis for liability and remediation decisions.

Additive Manufacturing & Thermal Processing

Dr. Preston brings specialized expertise in additive manufacturing (AM), powder metallurgy, and thermal processing — including field-assisted sintering technique (FAST) — that directly supports clients evaluating AM component quality, processing defects, and microstructure-property relationships. He has studied the effects of thermal and electrical gradients on microstructure evolution in stainless steels, titanium alloys, and ultra-high-temperature ceramics, and he has investigated additive manufacturing of metals, metal-metal composites, and cermets. This background enables him to assess whether AM or sintered components meet design intent and identify processing-related failure modes that may not be apparent through conventional inspection.