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Published on: January 16, 2019
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Controlling Fatigue Cracks in the Transmission Electron Microscope.
Andrew Baker1, Kyle R Dorman2, Khalid Hattar3
1Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87123, USA.
Small Methods
|October 16, 2025
Summary
Researchers developed a new method to control fatigue crack growth in situ Transmission Electron Microscopy (TEM) experiments. This quantitative approach allows detailed observation of nanoscale fatigue mechanisms in various materials and devices.
Area of Science:
- Materials Science
- Mechanical Engineering
- Nanotechnology
Background:
- Fatigue cracking poses significant economic and safety risks in engineering.
- In situ Transmission Electron Microscopy (TEM) offers insights into nanoscale fatigue origins.
- Current nanoindenter-based TEM methods for observing crack propagation lack precise control.
Purpose of the Study:
- To introduce a novel, quantitative control methodology for in situ TEM fatigue experiments.
- To enable detailed observation of nanoscale fatigue damage mechanisms.
- To provide a framework for comparing material responses to fatigue stress.
Main Methods:
- Adoption of a control methodology from linear elastic fracture mechanics.
- Utilizing a stress intensity factor (K) to quantify the driving force on fatigue cracks.
- Demonstration on nanocrystalline Platinum (Pt) alloys using in situ TEM.
Main Results:
- Successfully controlled fatigue crack growth over micrometers in situ.
- Enabled observation of nanoscale damage mechanisms: blunting, closure, deflection, branching, healing, and fatigue-induced grain growth.
- Established a quantitative basis for comparing material fatigue responses.
Conclusions:
- The novel stress intensity factor-based method offers precise control for in situ TEM fatigue studies.
- This approach facilitates the investigation of nanoscale cyclic degradation in diverse materials.
- The methodology is applicable to structural materials and advanced nanotechnology applications.
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