Quickly compare materials’ strength & elongation at break after hot air exposure

When selecting materials for applications exposed to continuous hot air, design engineers want to know how long a material’s strength and maximum elongation at break can be retained, upon exposure to hot air of 150°C or higher. With our Heat Aging Tool, you can quickly compare materials and see which one best retains strength and elongation at break.

As an engineer, who designs application parts that are exposed to continuous high temperatures, you know that tensile strength and maximum elongation at break depend on the potential oxidative ageing conditions of the material. Knowing how long the strength and maximum elongation at break can be retained when exposed to hot air of 150°C or higher is crucial when designing an application that will be exposed to high temperature oxidative ageing conditions.

Envalior’s Heat Aging Tool is very useful for engineers designing applications that are exposed to hot air, including automotive air management systems applications, such as hot air ducts, turbo charger hoses and seals. These automotive applications are located under a hood near a vehicle’s combustion engine, which experiences continuous high temperatures during its operating life.

You can pick the best material that can retain strength long enough upon oxidation at high temperatures

With the Heat Aging Tool you can compare materials to see which ones meet specific application requirements. Quickly find out the evolution of strength and strain at the break of a material upon ageing in hot air at a specified temperature.

You can also quickly and easily assess the maximum operation lifetime @ T specified for a specific material. The operation lifetime equals the time that is needed for the strength of the part @ specified thickness of 4mm to drop to 50% of its initial value. Knowing this data will help you guarantee the sufficient strength of an engineering part used at elevated temperatures during the part’s lifetime.

This tool offers two graphical representations of the degradation process of the tensile strength and elongation-at-break after oxidative ageing: the half-life time as well as decay-curves. Both the humidity during ageing as well as the humidity during the subsequent tensile test are taken to be 0% (in line with application temperatures and 100°C, i.e. materials are dry).

As a user you will need to input:

  • Grade selection
  • Maximum ageing time (used for decay graph)
  • Ageing temperature
  • Testing temperature

Tool output will include:

  • Time-dependent graphs showing the change in tensile strength or elongation-at-break over time.
  • Retention graphs showing the how well the original properties are retained over time on a scale of 0-100%.
  • Half-life graph showing the half-life time for various ageing temperatures (for either tensile strength or elongation-at-break).

Heat Aging Tool model

The Heat Ageing Tool is based on a large data set that covers heat ageing decay in hot air and chemical ageing in various liquids. These effects can be seen and are described by the overall model: an initial decrease often observed in chemical ageing, associated with moisture uptake; a longer-term decay associated with degradation of the polymer and an increase in strength due to crystallization effects.

This model is partly based on physical equations and extended with some mathematical sections necessary to adjust specific behavior seen in the available datasets as well as to interpolate measured data to nearby test-temperatures.

On average, the standard deviation (1 sigma) is around 5-10%. This engineering accuracy is indicated in the graph for each line by means of a semi-transparent confidence region.

For elongation at break, accuracy is less for specific grades. This is mainly due to an initial fast increase in elongation at break where in general very few datapoints are available.

At the moment, we are in the process of expanding the Heat Aging Tool to more grades, depending on the availability of experimental data as well as on the demand for particular grades. Let us know what grades you're looking for by filling in the feedback form on the bottom right of this page.


Robert Janssen

Rob Janssen was trained as a physical chemist at the University of Wageningen and holds a PhD from the Technical University of Eindhoven (TU/e) in polymer physics. After post-doctoral assignments at the University of Patras (in molecular simulation with Doros Theodorou) and ETH Zürich (with Paul Smith), he transferred to DSM in Geleen, the Netherlands. Now he is Principal Scientist for Functional Materials Properties at Envalior, formerly DSM Engineering Materials. His work is focused on building application insights, such as fuel cell and battery operation, and the translation into material property improvement programs, such as (di)electrics, breakdown voltage, EMI, CTI, thermal transport and stability, and flame retardancy.

Heat Aging Tool

Published on

04 August 2023


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