In Home

Hittech University ‘Materials’ 30 January 2020

30 January 2020 the second edition of the Hittech University colloquia, this time about ‘Materials’, took place. Four presentations informed our Hittech Colleagues as well as developers of our customers like ASML and VDL on theory and practice on two special materials: Invar and Duplex.

We had four outstanding speakers. Two from Academia: Prof. Krupp, Chair of the Institute für Eisenhüttekunde at Aachen University, who presented “Theory and Failure Mechanisms of Duplex” and Prof. Offermans, Materials Faculty TU Delft, who presented an introduction on Invar.
And two Hittech Colleagues: Koen Mentink, MD Hittech Bihca, and Ard Geelkerken, Teamleader Value Engineering at Hittech Multin, who introduced Practice on machining and design.

Invar is typical a material of which in-depth knowledge is of great importance. Often selected for its lowest coefficient of thermal expansion, one has to realize the drawbacks of this complex material. It is heavy, not corrosion resistant, expensive, the CTE is not linear and becomes 10 times larger at higher temperatures. Whereas machining often requires a heat treatment, because machining causes internal stresses which result in creep.
Koen Mentink presented his expertise in machining of Invar without causing dimensional instability.
Ard Geelkerken showed interesting and creative examples from his extensive design experience. He showed how to minimize the use of complex materials and how to incorporate cost of material and production in an integral design approach with an integral cost view.

Duplex is one of those few materials that can survive at 2 km below sea level due to its strength and resistivity against corrosion.
Extreme material characteristics however lead to a complex material, especially complex crystalline structure. Duplex is typically such a material. When a structure is dynamically loaded, the complex structure from materials like Duplex will lead to micro cracks and crack propagation along the crystalline structure leading to failure. Whereas the corrosive environment can speed up this process significantly.
The hardness and composition of Duplex makes it to a material hard to machine, resulting in high production cost and requires appropriate way of working and special tooling.
Koen Mentink presented the expertise and lessons learned from Hittech Bihca. A clear example showing the importance of material knowledge for designers!

The University was finalized by a walking dinner with discussions. Again a successful Hittech University; an inspiration to deepen and spread material knowledge and an inspiration for a third University!

If you are interested to learn more about this University and the Hittech knowledge on materials in design and production, please contact Pieter Kappelhof,

Start typing and press Enter to search