Innovative hardness testing technology at the Zurich University of Applied Sciences

Around 70% of all new products today are based on new materials and processes - these are often the key to innovation The manufacturing processes for products made using high-tech materials are demanding and call for a comprehensive knowledge of process technology in addition to a good knowledge of materials. The Institute of Materials and Process Engineering (IMPE) at the Zurich University of Applied Sciences (ZHAW) in Winterthur, Switzerland, combines these two disciplines in a practical way.

Subjects on which research and development at IMPE is focused include:
• polymers, ceramic and metallic coatings
• composite materials
• metal alloys (super alloys)
• joining technologies (bonding, welding).

IMPE has expanded its testing technology with the addition of two Zwick hardness testers for recording mechanical material characteristic values. The Mikro-Vickers hardness tester covers Vickers and Knoop hardness tests and possesses a motor-operated fixture turret for lenses and indenters. In addition, an overview image of the specimen surface can be generated via stitching and multiple hardness traverse tests performed automatically.

The second hardness tester is equipped with digital measurement and control technology plus a load cell and digital measuring transducer. As well as the classical Vickers, Brinell and Rockwell hardness testing methods, the tester also performs instrumented indentation tests to ISO14577. This method, together with cyclic indentation testing with an increasing load, is preferred for characterization of new materials and optimization of existing ones. These methods also enable quantification of minor deviations in material characteristic values.

“With the ZHU2.5 testing system we are in the happy position of being able to perform fully automatic hardness tests, which is, of course, of particular value in hardness traverse testing, for example on weld seams or heat-treated components. Moreover, thanks to the instrumentation we can for the first time characterize the mechanical properties of materials by quasi-non-destructive testing – Young’s modulus for metals, for example, or creep or relaxation behavior for polymers,“ states Christian Scherer, research associate at the ZHAW.