Which materials can a failure analysis be performed on?
MaterialScan carries out analysis on several materials and products. In particular, the great experience gained in technical support to customers allows us to offer professional services in the following areas:
- Structures and components made of steel and other metal alloys
- Failure analysis on plastics (e.g. extruded or moulded parts) and rubber (e.g. seals)
- Composite materials with thermoplastic and thermosetting matrix
- Advanced ceramics
- Paints, varnishes and coatings
When a failure analysis is performed?
Failure analysis is performed when a system, equipment or component is subjected to an early, sudden or unexpected failure.
The key principles of this analysis are applicable to any branch of the manufacturing sector since the triggering factors can be divided into three specific classes:
- Chemistry and microstructure of the material
- Manufacturing process parameters and operating conditions
- Influence of external factors such as an aggressive environment, thermal or mechanical load conditions.
FAILURE ANALYSIS ON PLASTICS
MaterialScan is qualified in chemical characterization of the main polymer classes (thermoplastics, thermosettings and elastomers) by means of Fourier Transform Infrared (FTIR) spectroscopy.
Data are elaborated by our experts in order to identify which polymers are present in the sample and to give information about crystallinity degree, thermal, chemical and environmental degradation.
Infrared spectroscopy analysis on plastics and rubber is performed in accordance with ASTM E1252 and ISO 4650 respectively.
Using differential scanning calorimetry (DSC), our laboratory can determine the temperature and enthalpy of fusion and crystallization, glass transition temperature, decomposition temperature, crystallinity degree and phases (fillers, blends, copolymers).
Differential scanning calorimetry (DSC) measurements on plastics are performed according to the main international standards (ISO 11357, ASTM D3418 e ASTM E793).
Using a universal testing machine, we can measure the mechanical properties of plastics up to 280°C. The testing machine is equipped with a 10 kN load cell (high precision type 1/500, ±0,5%), wedge grips, compression plates, three-point bending test jig and the crosshead speed varies in the range 0,001 ÷ 1000 mm/min.
The following tests can be performed, as an example:
- Tensile test (ASTM D638 and ISO 527)
- Bending test (ASTM D790 and ISO 178)
- Compression test (ASTM D695, ISO 3386 and UNI EN ISO 604)
- Peel test (ASTM D1876)
In addition, we can evaluate impact resistance of plastics by means of a Charpy pendulum (ISO 179).
FAILURE ANALYSIS ON METALS
Metallographic examination and indentation hardness tests
The mechanical properties of metals, such as steel, cast iron and non-ferrous alloys (aluminium, copper, nickel, etc.) are strongly influenced by their chemical composition and microstructure. After accurate preparation and polishing, samples are carefully evaluated focussing particular attention on the effects of heat treatments and processing on:
- phase distribution
- grain dimension
- steel microstructure (austenite, ferrite, pearlite, martensite, sorbite, bainite)
- inhomogeneities and non-metallic inclusions.
Visual examination both macroscopic (with optical microscope) and microscopic (by means of metallographic microscope with a magnification greater than 50x) are performed in compliance with international standards.
We can employ scanning electron microscopy (SEM) combined with EDS microanalysis if a more detailed evaluation is required to characterize, for example, fracture morphology (mechanical or stress corrosion cracks, dimples) and oxidized or corroded surfaces.
Indentation hardness tests (Brinnel, Rockwell, Vickers) can evaluate rapidly the resistance to indentation of metal components after heat or thermochemical treatments, such as cementation and nitriding.
All indentation hardness test methods performed in our laboratory are compliant with UNI and ASTM standards.