ADVANCED MATERIALS & PROCESSES | JANUARY 2026 28 Compressive Failure. Compressive failures are the result of a material or component failing due to axial loading in compression. The failure may result in buckling or bulging in ductile materials. Excessive axial compressive loading can result in cracking and fracture in brittle materials. Creep Failure. Creep failures are a result of a material or component’s gradual change in size or shape due to continual applied stress. They are similar to yielding failures with the exception that creep failures are time- dependent occurring under stress[4]. Creep failures are common in engine components and other assemblies that operate at relatively high temperatures while under stress. IDENTIFCATION OF THE FAILURE PROGRESSION In addition to subcategories within failure mechanisms and modes, it is important to understand that the failure of a material or component may begin in one failure mode, propagate via a different mechanism, and end in a different mode. This is where a trained metallurgist or materials engineer is vital to the investigation process. If the exact initiation, propagation, and final failure mode are not correctly identified, the entire investigation will be compromised and the TRC will not be determined. The combinations of failure initiation (source), propagation (mechanism), and final failure mode are nearly endless. As presented in this article, the intricacies and nuances of a failure identification and determination of the source represent a complex process. The entire process must be a team effort if it is to be successful. Simply relying on one individual to accomplish such a complex process is a recipe for failure in itself. Figure 1 illustrated the progression of a failure. As a follow up, Table 2 provides a few basic examples of the relationship of the three stages of a failure progression. SUMMARY Only after the failure mode(s) have been correctly and completely identified, the failure mechanisms deter- mined, and the failure origin(s) identified can the investigation proceed to determine the TRC “why” of the failure. Understanding each of these aspects and determining the TRC of a failure event is the ultimate goal of a successful failure investigation. The next and final installment of this series, to be published in a future issue of AM&P, will provide a detailed process for a systematic failure investigation based on the author’s experience. ~AM&P For more information: Jeffrey L. Hess, retired manager of metallurgy and quality engineering, Auburn Gear LLC, Auburn, IN 46706, jlhess50@gmail.com. References 1. https://www.merriam-webster.com/ dictionary/failure. 2. R.J. Shipley, B.A. Miller, and R. J. Parrington, Introduction to Failure Analysis and Prevention, Failure Analysis and Prevention, Volume 12, ASM Handbook, ASM International, Materials Park, Ohio, p 1-24, 2021. 3. https://www.merriam-webster.com/ dictionary/fatigue. 4. D.J. Wulpi, Understanding How Components Fail, third edition, ASM International, Materials Park, Ohio, p 57, 2013. TABLE 2 — STAGES OF FAILURE PROGESSION Failure source (“why”) Failure mechanism (“how”) Failure mode (“what”) Incorrect material Excessive loading (overload) Brittle fracture Design flaw (sharp notch effect) Cyclic loading (fatigue) Fatigue fracture Poor maintenance Lack of lubrication (wear) Wear failure Improper plating Environment (corrosive) Corrosion failure Assembly error Over torquing bolt (overload) Ductile failure ADVANCE YOUR CAREER WITH A FAILURE ANALYSIS CERTIFICATE OF ACHIEVEMENT The Failure Analysis Certificate of Achievement is a unique skill-boosting opportunity offered by ASM International. This comprehensive program examines practical failure analysis, with a wide range of elective courses on related topics such as component failure analysis, corrosion, fractography, mechanical testing, metallography, and inspection. Earn a career-enhancing certificate in around 30 hours of training with test-out options available for select courses. As an IACET Accredited Provider, ASM Inter- national offers IACET CEUs for its learning events that comply with the ANSI/IACET Continuing Education and Training Standard. Learn more at asminternational.org/ learning/certification.
RkJQdWJsaXNoZXIy MTYyMzk3NQ==