A new instrumented notched impact tester with a working capacity of 300 J was successfully tested for the first time during a preliminary acceptance test at the manufacturer ZwickRoell. The first acceptance tests were carried out on the device, which will soon be installed at the Leibniz Institute for Materials Testing in Bremen, under the supervision of Dr Andree Irretier.

The device makes it possible for the first time to test the fracture mechanical properties of various materials under cryogenic ambient conditions of up to 10 K (-263 °C), i.e. at extremely low temperatures. In the new instrumented notched impact tester, materials with a working capacity of 300 J can be tested according to DIN EN ISO 14556. This is particularly relevant in recent research on the storage of liquid hydrogen. With the help of the new testing machine, tests can now also be carried out to determine and evaluate the fracture-mechanical behaviour of materials at the typically prevailing storage temperatures of liquid hydrogen (21 K or -252 °C). This can provide important insights for current research: Which material-relevant factors interact during the storage and transport of liquid hydrogen? And which factors need to be taken into account and possibly optimised further? These questions are now being answered piece by piece with the help of the new testing machine.

The first test carried out in the testing machine was definitely impressive. Here, an impact test specimen made of X5CrNi18-10 was shattered at a test temperature of 15 K (-258 °C). A force of over 25,000 N was measurable in the first two milliseconds of the test. The notched impact energy consumed was 85 J.
In this context, the Institute would like to thank the state of Bremen for its support.

Photo above: Instrumented notched impact tester HIT750P and temperature control unit, (c) ZwickRoell, in-house exhibition October 2022

Instrumented notched bar impact test (working capacity 300 J) on X5CrNi18-10 at a test temperature of 15 K (KV=85 J)