Institute for Applied Materials – Materials Science and Engineering

Competence

In the framework of the research of the group "Production and Component Behaviour" the interactions between production processes, component state and component behaviour at mechanical loading are investigated. The production processes considered are available either in the laboratories of production techniques of IAM-WK or within cooperations with institutes of production sciences. They are subdivided into the main groups of production processes according to DIN as follows:

Moulding

  • Micro Powder Injection Moulding
  • Micro Casting
  • Casting

Cutting

  • High Speed Cutting
  • Micromachining, Microerosion
  • Laser ablation

Altering of Materials Properties

  • Altering of Materials Properties
  • Case Hardening of Steels
  • Laser Hardening
  • Shot Peening
  • Deep Rolling
  • Laser Schock Peening

A main subject of the research of the section "Production and Component Behaviour" is the characterisation of production induced component or surface states using metallographic and x-ray methods, which are available from the corresponding sections of the institute. microstructure and properties structure and stress analysis.

Besides this devices of the laboratories of production techniques and the laboratories of mechanical testing are involved in the determination of the stability of surface layer states at thermal, quasistatic, cyclic and combined loadings. Additionally, in the laboratories for mechanical testing the effects of production induced component states on strength, especially fatigue strength, of metallic and ceramic materials are investigated.

An additional important main subject of the research of the section "Production and Component Behaviour" is the Simulation of the generation of productopn induced component states at different production steps. Here, different Finite-Element-Programmes Numerical Simulation are used to describe especially thermo-mechanically coupled processes, if necessary including phase transformations. The necessary input data are determined experimentally Laboratory of production technoiques.


heat treatment mühl
Heat Treatment

Heat treatment from the main group "Changing material properties" includes processes or process chains for thermal, thermo-chemical and thermo-mechanical treatment of workpieces. The component properties, which are important in many applications, are adjusted by specific heating and cooling phases and the resulting phase transformations via the microstructure composition, the residual stress state and the hardness. In heat treatment, a fundamental distinction is made between processes that cause a radical structural transformation and processes that only cause a transformation on the surface of a workpiece. The first-mentioned processes include annealing and hardening, i.e. thermal processes. The second-mentioned processes count as diffusion and coating processes as well as thermochemical processes. The thermochemical surface hardening processes are mainly characterised in series production by a significant increase in surface hardness and lifetime at low unit costs. On the one hand, it is intended to achieve high surface layer hardness in order to minimize the wear. On the other hand, the microstructure and residual stress depth profiles are specifically adjusted, which usually leads to an extension of the durability. The current research focus is the optimization of heat treatment processes for components that are difficult to access. The adjustment of mixed microstructures to improve the mechanical properties is another important aspect. The goal is to improve fatigue properties compared to the conventional quenching and tempering processes by adjusting different microstructure components.

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Mechanical Surface Treatment

Mechanical surface treatment comprises a number of processes from the main manufacturing group "Modification of material properties", which are used to improve the component behaviour under operational loads. Mechanical surface treatments include, for example, shot peening, deep rolling, machine hammer peening, and some other processes that are used in customized industrial applications. The mechanical surface treatment of a component causes plastic deformation of its surface layer, resulting in local work hardening and the formation of residual compressive stresses. In particular, the processes deep rolling and machine hammer peening can also be used to smooth and structure surfaces due to their deterministic nature. A combination of smooth surface, work hardening and residual compressive stresses is particularly advantageous for improving the service life properties in the fatigue stress frequently encountered in mechanical, automotive and aircraft engineering. Structured surfaces, such as bionic ones, can also be created to optimize wear behavior. The focus of the research work in the department "Manufacturing and Component Behavior" is on the new and further development of processes, the identification of the relationships between process parameters, surface layer characteristics and component behavior, as well as numerical process simulation and modeling for the prediction of surface layer properties and component behavior. Furthermore, we deal with thermomechanical surface treatments, such as shot peening at elevated temperature or machine hammer peening under cryogenic conditions. Also in the context of additive manufacturing, mechanical surface treatments are used as final processes or processes switched within the build-up to optimize surface layer and component properties. This illustrates the intensive interdependence of the issues considered within the department "Production and component behaviour".

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slm chuan
Additive Manufacturing

Additive manufacturing (AM) is characterized, in comparison to conventional manufacturing processes, by the layer-wise build-up of the three-dimensional shape of the component directly from the CAD geometry. Basic materials are metal powder, metal or polymer filaments as well as resins and inks which are consolidated by energy input or chemical cross-linking. The main energy sources used today are laser or electron beams and electrically or inductively heated extrusion heads. Due to the direct production of the component without geometry-bound tools or moulds, additive manufacturing plays a pioneering role, especially in the field of advanced manufacturing. The continuous digitalization and automation of the process chain, the products with high design complexity as well as the possibility of function integration enable additive manufacturing to be used more and more intensively as an innovative technology in various applications. Due to the layered build-up with a specific exposure or deposition strategy of the base material, additive manufactured components not only have a characteristic microstructure but also process-related defects (pores, voids, cracks). The knowledge of the underlying causes in connection with the process control as well as the effect on component properties and component behaviour is fundamental for the application of additively manufactured structural components. At the same time, the highly localised process zone (e.g. in the melt pool or during filament extrusion) offers the possibility of controlling the microstructure and defect structures in a targeted manner. This requires precise control of the temperature history and the exposure/deposition strategy from the melt pool via the individual layer to the entire component. Due to these complex dependencies in the process-structure-property relationships, especially the reproducibility and testing of additively manufactured components is still a largely open field of research.

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simu iam-wk
Material Modelling and Process Simulation
ct iam-wk
Non-destructive Material Characterization