A5017427828- Advanced Machining and Optimization Techniques
- Advanced Surface Polishing Techniques
- Advanced machining processes and optimization
- Metal and Thin Film Mechanics
- Composite Material Mechanics
- Microstructure and Mechanical Properties of Steels
- Metal Alloys Wear and Properties
- Numerical methods in engineering
- High Entropy Alloys Studies
- Microstructure and mechanical properties
- Corrosion Behavior and Inhibition
- Additive Manufacturing Materials and Processes
- Rheology and Fluid Dynamics Studies
- Surface Treatment and Coatings
- Advanced Mathematical Modeling in Engineering
- Metallurgical Processes and Thermodynamics
- Electronic and Structural Properties of Oxides
- Advancements in Solid Oxide Fuel Cells
- Nonlocal and gradient elasticity in micro/nano structures
- Engineering Applied Research
- Epoxy Resin Curing Processes
- Composite Structure Analysis and Optimization
- Fiber-reinforced polymer composites
RWTH Aachen University
2015-2022
In components under bending load the top layer of workpiece is strained most. The properties this are therefore very crucial for mechanical behavior component as a whole. Wire-EDM process, like every machining interacts with surface by thermal material and modification. removal principle in creates characteristic rim zone alteration. process generates especially an outer shell that known white layer. Although generally reducing endurance, precise structure composition unknown....
Adjusting a resulting surface integrity prior to manufacturing process is big challenge in production engineering. One approach solve this the methodology of signatures. To develop comprehensive signature for Sinking EDM (S-EDM) it necessary describe relationship between applied material loadings and modifications workpiece rim zone. It generally considered that S-EDM an electro-thermal process, which significantly characterized by heat flux due spark plasma. Accordingly, main during are...
In contrast to most other manufacturing technologies, in electrochemical machining processes only slight changes material characteristics the rim zone of workpieces are stated literature. Due physical active principle, no thermo-mechanically induced phase or evolution a so-called white layer were ever observed. Aside this fact, not inconsiderable number smaller modifications found past. The common effects occurring during generation passive on surface by changing local chemical composition...
The surface and subsurface conditions of components are significant for their functional properties. Every manufacturing process step changes the condition due to its mechanical, chemical and/or thermal impact. depth affected zone varies different machining operations, is predetermined by parameters characteristics. Furthermore, initial state has a decisive influence on interactions that lead final conditions. aim investigation presented here compare load characteristics over applied...
In comparison to steel, titanium alloys react differently the choice of process parameters in sinking electrical discharge machining (EDM), especially concerning applied polarity tool. With an anodic tool polarity, EDM removal on Ti6Al4 V is scarce due carbide formation, while steel occurs as expected. To understand behavior alloys, a comparative study between and iron single successive experiments performed. Ironically, with both alloys. However, ten discharges experiments, increases...
Wire electrochemical machining (wire ECM) combines the advantages of wire electrical discharge EDM) and (ECM). The flexible 2.5 dimensional without need for an application-specific fixture are combined with excellent surface integrity properties ECM. These make process particularly suitable highly critical components, like fir tree slots in turbine discs. Knowledge resulting terms microstructure formation, oxide layers, etc. is essential such components. Therefore, this paper modified rim...
One particular kind of engineered grinding wheels are precisely profiled tools with flattened coarse diamond grains, primarily used for machining brittle materials. Because their grain geometries, they also expected to introduce mechanical strains into steel workpieces generating a work hardening effect. Also low surface roughnesses combined favorable compressive residual stresses targeted. In this paper the feasibility process technology is investigated and possible adverse aspects...
The surface and subsurface conditions of components are critical for their functional properties. Every manufacturing process modifies the condition as a consequence its mechanical, chemical, thermal impact or combinations three. depth affected zone varies different machining operations is related to parameters characteristics. Furthermore, initial material state has decisive influence on modifications that lead final conditions. With this knowledge, collaborative research center...
Since the term surface integrity was introduced in 1964 by Field and Kahles, final processing step its influence on microstructure heavily investigated. In particular, a lot of research connection to functional properties workpiece like life time wear resistance has been performed. However, process chain industrial applications most not taken into account, although former manufacturing steps do affect result. this work, samples ferrite-perlite 42CrMo4 steel (AISI 4140) were first processed...
Properties of workpieces, like residual stress in the rim zone, cannot be predicted for manufacturing technologies reproducible advance. This lack predictability shall solved by a new approach, called Process Signatures. These Signatures will combine material loadings forced process with change state variables, e. g. variation surface layer. As achieve comparability different processes same physical working principle, it is necessary to describe transition from properties uniform way....
During machining, the machined surface is modified due to thermal, mechanical and chemical loads applied by used process. Temperature, temperature gradients, strain gradients lead a change of microstructure in zone. Internal material are difficult access experimental measuring methods during processing. Therefore, this work aims at solving inverse problem determining resulting internal thermal grind hardening based on characterized modifications. hardening, high workpiece. This leads phase...
A large-chamber scanning electron microscope (LC-SEM) provides an ideal platform for the installation of large-scale in situ experiments. Our LC-SEM has internal chamber dimensions 1,2 × 1,3 1,4 m3 (W H D) (Fig.1) and makes it possible to incorporate novel experimental devices, which are reported on here. The present manuscript describes detail development test equipment study a broad range processes production engineering. Direct observation materials modification mechanisms fundamental...
Process Signatures describe the relationship between applied material loads and resulting surface modification according to predominant effect of production process used. This approach is supposed allow adjustment layer properties prior process. In this paper, modifications turned, turned + deep rolled metastable austenitic steel with predominantly thermo-mechanical/ mechanical effects are analyzed by electron microscopic methods like Electron Backscatter Diffraction (EBSD) Transmission...
Abstract The purpose of this work is the multiscale FE‐FFT‐based prediction macroscopic material behavior, micromechanical fields and bulk microstructure evolution in polycrystalline materials subjected to mechanical loading. boundary value problem (BVP) solved using implicit finite element (FE) methods. In each integration point, microscopic BVP embedded, solution which found employing fast Fourier transform (FFT), fixed‐point Green's function mean response determined by stress‐strain...
Abstract The oxygen transport membrane Ba 0.5 Sr Co 0.8 Fe 0.2 O 3-δ (BSCF) was wetted by the reactive air brazing alloy Ag-14CuO. Triple point phases of different cobalt-copper-oxides are formed in reaction zone and origin micro-cracks stress concentration. Therefore, their identification is necessary for understanding microstructure evolution designing interface structure advantageously an adapted process. However, as cobalt-copper-oxide system can form many oxides with solubility Cu...
Abstract Electrochemical machining is based on the anodic dissolution of most metals and generates high quality polished surfaces. However, ferrite‐perlite 42CrMo4 steel reveals local optical changes at surface after electrochemical finishing, such as a widely variable finish from shiny (reflective) to rough (dark) surfaces even one processing step. The different areas (AISI 4140) are studied by electron microscopy techniques, x‐ray diffraction photoelectron spectroscopy gain information...