95 research outputs found
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Influence of Heat-Treatment of Selective Laser Melting Products - e.g. Ti6Al4V
Usually additive manufactured metal parts are showing a different mechanical behavior compared to
conventionally produced parts used the same material. Apart from process-related macroscopic part
imperfections (pores, surface roughness, etc.) the microstructure has a decisive influence on the mechanical
properties of the materials. Thus, in order to optimize mechanical properties of metal parts a heat treatment for
changing microstructures is routinely applied in most production lines to meet the product requirements. By
means of the Titanium alloy Ti6Al4V the optimization of the static- and the fracture mechanical behavior by
changing the microstructure with a heat treatment after the SLM process is discussed on the present work.Mechanical Engineerin
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Systematical Determination of Tolerances for Additive Manufacturing by Measuring Linear Dimensions
Additive manufacturing offers many technical and economical benefits. In order to profit
from these benefits, it is necessary to consider the manufacturing limits and restrictions. This
applies in particular to the geometrical accuracy. Therefore, the achievable geometrical accuracy
needs to be investigated, which enables the determination of realistic tolerances. Thus, two
different aims are considered. The first aim is the determination of dimensional tolerances that can
be stated if additive manufacturing is used under normal workshop conditions. Within the second
aim, relevant process parameters and manufacturing influences will be optimized in order to reduce
dimensional deviations. To achieve both aims a method was developed first. This method identifies
relevant influential factors on the geometrical accuracy for the processes Fused Deposition
Modeling (FDM), Laser Sintering (LS) and Laser Melting (LM). Factors were selected that are
expected to affect the geometrical accuracy mainly. The first investigations deal with measuring
linear dimensions on a designed test specimen and the derivation of achievable dimensional
tolerances. This paper will present both, the developed method and the first results of the
experimental investigations.Mechanical Engineerin
Processing Parameter Effects on Residual Stress and Mechanical Properties of Selective Laser Melted Ti6Al4V
Selective laser melting (SLM) process is characterized by large temperature gradients resulting in high levels of residual stress within the additively manufactured metallic structure. SLM-processed Ti6Al4V yields a martensitic microstructure due to the rapid solidification and results in a ductility generally lower than a hot working equivalent. Post-process heat treatments can be applied to SLM components to remove in-built residual stress and improve ductility. Residual stress buildup and the mechanical properties of SLM parts can be controlled by varying the SLM process parameters. This investigation studies the effect of layer thickness on residual stress and mechanical properties of SLM Ti6Al4V parts. This is the first-of-its kind study on the effect of varying power and exposure in conjunction with keeping the energy density constant on residual stress and mechanical properties of SLM Ti6Al4V components. It was found that decreasing power and increasing exposure for the same energy density lowered the residual stress and improved the % elongation of SLM Ti6Al4V parts. Increasing layer thickness resulted in lowering the residual stress at the detriment of mechanical properties. The study is based on detailed experimental analysis along with finite element simulation of the process using ABAQUS to understand the underlying physics of the process
Survey team on : conceptualisations of the role of competencies, knowing and knowledge in mathematics education research
This paper presents the outcomes of the work of the ICME 13 Survey Team on 'Conceptualisation and the role of competencies, knowing and knowledge in mathematics education research'. It surveys a variety of historical and contemporary views and conceptualisations of what it means to master mathematics, focusing on notions such as mathematical competence and competencies, mathematical proficiency, and mathematical practices, amongst others. The paper provides theoretical analyses of these notions-under the generic heading of mathematical competencies-and gives an overview of selected research on and by means of them. Furthermore, an account of the introduction and implementation of competency notions in the curricula in various countries and regions is given, and pertinent issues are reviewed. The paper is concluded with a set of reflections on current trends and challenges concerning mathematical competencie
Fatigue strength estimation methodology of additively manufactured metallic bulk material
International audienc
Automated Multi-Scale Microstructure Heterogeneity Analysis of Selective Electron Beam Melted TiAl6V4 Components:english
Fatigue behavior of thin-walled grade 2 titanium samples processed by selective laser melting. Application to life prediction of porous titanium implants
An investigation into melting modes in selective laser melting of Inconel 625 powder: single track geometry and porosity
Assessing the Development of Educational Research Literacy: The Effect of Courses on Research Methods in Studies of Educational Science
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