Volume 73, Issue 1

While experimental high-throughput and computational methods exist for the development of functional materials, structural materials are still being developed on the base of experience, stepwise prediction and punctual support of computational models. As a result, many major breakthroughs have been and still are achieved by coincidence under non-intuitive conditions. Experimental high throughput methods allow to explore large process windows where no prediction is possible due to lack of existent data. This work proposes the high throughput method “Farbige Zustände” as a novel approach for the experimental exploration of structural materials. New methods for sample synthesis, treatment and characterization are developed as well as computational methods for ad-hoc data analysis, search and experiment planning.

In industrial production, the absence of clear component identification and unrecognized component defects can lead to a lack of protection against product piracy and unforeseen faults in machinery and equipment. In this context, data, which are stored directly in the subsurface region of a component ensuring its clear identification, as well as sensitive materials which act as sensors for high loading, can contribute to problem-oriented solutions. For robust, forgery-proof component identification that is inseparably linked to the component, three-dimensional data matrix codes are introduced into the component's subsurface region via a laser-induced local heat treatment. This technology ensures a sufficient data density. By locally tempering the metastable austenitic steel, areas are created where mechanical loads exceeding a defined level cause changes in the microstructure of the heat treated subsurface region. By means of adapting suitable read-out technologies, such as high-resolution eddy-current technology and the harmonic analysis of eddy-current signals, the data and load information stored in the component's subsurface region can be read non-destructively.

Rolling element bearings in aeroengine applications undergo high stresses and elevated temperatures. Besides through hardening grades, predominantly the high speed steel M50, often case hardening steels, mostly the high performance carburizing steel M50NiL, are used in critical aircraft engine applications. The advantage of case hardened steels compared to through hardened steels is a relatively high fracture toughness in the core. Furthermore, carburizing steels allow an integrated functional design. Sophisticated heat treatment cycles are necessary to get optimal microstructural properties. This paper presents properties of these steels and experiences in industrial processing, especially in carburizing and hardening.

Titanium aluminum nitride (TiAlN) coatings are frequently used for cutting applications because of their high wear resistance and high thermal stability. Doping with additional elements and a multilayered film structure can significantly improve the wear resistance of these hard coatings. For this context, the wear resistant of TiAlN based multilayer film systems was investigated. Films with different contents of chromium, zirconium and silicon were deposited by reactive DC magnetron sputtering on cemented tungsten carbide (WC/Co) milling inserts. Doping content and layer thickness were varied by the target power. Chemical composition, microstructure, adhesion, hardness and tool life time was analyzed by glow discharge optical emission spectroscopy (GDOES), electron microscopy, scratch tests, hardness indentation tests and milling tests. An industrial TiAlN coating was used as reference for the cutting test. Milling inserts coated with TiAlN/Cr X N and TiAlN/ZrN films showed no improved life time in comparison to the TiAlN reference, whereas the lifetime of the TiAlN/Si X N Y coated milling inserts was enhanced significantly for silicon contents up to 1.8 at.-%. A further increase of the silicon content the resulted in a significant decrease of adhesion and cutting performance.