Application Note | Fracture Surface Analysis
Fractography Analysis of a Steel Fracture Surface Using 3D Profilometry
Nano-to-Macro 3D Measurement of a Fractured Steel Surface as an Alternative to Microscope and SEM
Research & Experimental Testing
Craig Leising
Visual Design & Editorial
Andrew Shore
Introduction
Fractography is the study of features on fractured surfaces and has historically been investigated via Microscope or SEM. Depending on the size of the feature, a microscope (macro features) or SEM (nano and micro features) are selected for the surface analysis. Both ultimately allowing for the identification of the fracture mechanism type. Although effective, the Microscope has clear limitations and the SEM in most cases, other than atomic-level analysis, is unpractical for fracture surface measurement and lacks broader use capability. With advances in optical measurement technology, the NANOVEA 3D Non-Contact Profilometer is now considered the instrument of choice, with its ability to provide nano through macro-scale 2D & 3D surface measurements.
Why Use a 3D Non-Contact Profilometer for Fracture Inspection
Unlike an SEM, a 3D Non-Contact Profilometer can measure nearly any surface, sample size, with minimal sample prep, all while offering superior vertical/horizontal dimensions to that of an SEM. With a profiler, nano through macro range features are captured in a single measurement with zero influence from sample reflectivity. Easily measure any material: transparent, opaque, specular, diffusive, polished, rough etc. The 3D Non-Contact Profilometer provides broad and user-friendly capability to maximize surface fracture studies at a fraction of the cost of an SEM.
ℹ️ Learn more about non-contact profilometry lab services for fracture and failure analysis.
Measurement Objective
In this application, the NANOVEA ST400 is used to measure the fractured surface of a steel sample. In this study, we will showcase a 3D area, 2D profile extraction and surface directional map of the surface.
NANOVEA ST400 Standard
Optical 3D Profilometer
Results: Top Surface
Top Surface: 3D Surface
Top Surface: 3D Surface Texture Direction
| Texture parameter | Value |
|---|---|
| Isotropy | 51.26% |
| First Direction | 123.2° |
| Second Direction | 116.3° |
| Third Direction | 0.1725° |
Texture isotropy and directions of the top surface.
Top Surface: 2D Profile Extraction
Fig. 3: Location and 2D profile extracted from the top surface. Surface area, volume, roughness and many others can be automatically calculated from this extraction.
Results: Side Surface
Side Surface: 3D Surface
Side Surface: 3D Surface Texture Direction
| Texture parameter | Value |
|---|---|
| Isotropy | 15.55% |
| First Direction | 0.1617° |
| Second Direction | 110.5° |
| Third Direction | 171.5° |
Texture isotropy and directions of the side surface.
Side Surface: 2D Profile Extraction
Fig. 6: Location and 2D profile extracted from the side surface. Surface area, volume, roughness and many others can be automatically calculated from this extraction.
Conclusion
In this application, we have shown how the NANOVEA ST400 3D Non-Contact Profilometer can precisely characterize the full topography (nano, micro and macro features) of a fractured surface. From the 3D area, the surface can be clearly identified and subareas or profiles/cross-sections can be quickly extracted and analyzed with an endless list of surface calculations. Sub nanometer surface features can be further analyzed with an integrated AFM module.
Additionally, NANOVEA has included a portable version to their Profilometer line-up, especially critical for field studies where a fracture surface is immovable. With this broad list of surface measurement capabilities, fracture surface analysis has never been easier and more convenient with a single instrument.
Frequently Asked Questions About Fractography and Fracture Surface Measurement
What is fractography?
Fractography is the study of features on fractured surfaces, used to identify the fracture mechanism. It has historically been carried out with an optical microscope for macro features or an SEM for nano and micro features.
Why use a 3D profilometer instead of an SEM for fracture analysis?
A 3D non-contact profilometer measures nearly any surface and sample size with minimal sample preparation, captures nano through macro features in a single measurement with zero influence from reflectivity, and offers superior vertical and horizontal dimensions to an SEM, at a fraction of the cost.
What does surface texture direction show on a fracture?
The texture direction map gives the dominant directions of surface features and the isotropy of the surface. On this steel fracture, the top surface measured 51.26% isotropy with a first direction of 123.2°, while the side surface measured 15.55% isotropy with a first direction of 0.1617°.
What can be extracted from a 3D scan of a fracture surface?
Subareas, 2D profiles and cross-sections can be extracted and analyzed, and surface area, volume, roughness and many other parameters calculated automatically from the extraction.
Can fracture surfaces be measured in the field?
Yes. NANOVEA offers portable profilometers, which are especially useful for field studies where a fracture surface cannot be moved.
Which NANOVEA instrument was used for this fractography study?
The NANOVEA ST400 3D Non-Contact Profilometer. Sub-nanometer features can be analyzed further with an integrated AFM module.
