Suche
Anzeige der Dokumente 1-10 von 10
Aufsatz
Additive Manufacturing of 3D Luminescent ZrO2:Eu3+ Architectures
(2022-04-27)
Implementation of more refined structures at the nano to microscale is expected to advance applications in optics and photonics. This work presents the additive manufacturing of 3D luminescent microarchitectures emitting light in the visible range. A tailor-made organo-metallic resin suitable for two-photon lithography is developed, which upon thermal treatment in an oxygen-rich atmosphere allows the creation of silicon-free tetragonal (t-) and monoclinic (m-) ZrO₂. The approach is unique because the tailor-made ...
Aufsatz
Structural reorientation and compaction of porous MoS₂ coatings during wear testing
(2022-04-02)
Industrial upscaling frequently results in a different coating microstructure than the laboratory prototypes presented in the literature. Here, we investigate the wear behavior of physical vapor deposited (PVD) MoS2 coatings: A dense, nanocrystalline MoS2 coating, and a porous, prismatic-textured MoS2 coating. Transmission electron microscopy (TEM) investigations before and after wear testing evidence a crystallographic reorientation towards a basal texture in both samples. A basal texture is usually desirable due ...
Aufsatz
Microcantilever Fracture Tests of α-Cr Containing NiAl Bond Coats
(2022-01-08)
MCrAlY bond coats are widely used as oxidation-resistant coatings on superalloys. The major phase is the thermally stable intermetallic β-NiAl phase. The addition of Cr increases the oxidation and corrosion resistance but leads to the formation of α-Cr precipitates. Both phases are brittle and limit the fracture toughness of these coatings. To study the influence of thermal exposure and the resulting changing chemical composition on the fracture properties, the fracture toughness of both phases is measured by notched ...
Aufsatz
Investigation of processing windows in additive manufacturing of AlSi10Mg for faster production utilizing data-driven modeling
(2022-04-29)
To reduce production time and decrease production cost, the increase of layer thickness is an adequate option in powder bed fusion. In order to determine the relationships between process parameters in laser powder bed fusion (PBF-LB/M) and final porosity in AlSi10Mg, samples were processed following a space-filling experimental design in the present study. A total of 144 samples were fabricated considering layer thicknesses of 30 µm, 45 µm, 60 µm, and 90 µm. Afterwards, porosity was assessed using image analysis and ...
Aufsatz
On the influence of ϰ-carbides on the low-cycle fatigue behavior of high-Mn light-weight steels
(2021)
High-manganese light-weight steels offer a great potential for structural purposes in the mobility sector due to their reduced density combined with outstanding mechanical properties. As many of the envisaged applications of these materials will suffer from cyclic loading during their service life, the fundamentals of their fatigue behavior must be studied extensively. In the present work, the low-cycle fatigue (LCF) properties of an austenitic Fe-29.8Mn-7.65Al-1.11C light-weight steel were investigated. Two ...
Aufsatz
On the structural integrity of Fe-36Ni Invar alloy processed by selective laser melting
(2020)
Specimens made from pre-alloyed Invar (Fe-36Ni) powder were fabricated by selective laser melting and stress-relief heat treated afterwards. A relative density of the fabricated parts of 99.6 % was determined by computed tomography. The microstructure and mechanical behavior under monotonic and particularly cyclic loading at ambient temperature were investigated. Results reveal a bimodal microstructure containing columnar and equiaxed grains with an average grain size of 75 μm and pronounced texture 〈001〉 || BD. The ...
Konferenzveröffentlichung
On the Challenges toward Realization of Functionally Graded Structures by Electron Beam Melting—Fe-Base Shape Memory Alloy and Stainless Steel
(ASTM International, 2020-09-22)
In the present study, an iron-manganese-aluminum-nickel (Fe-Mn-Al-Ni) shape memory alloy was processed on an austenitic steel (AISI 304) build platform by electron beam melting in order to study the feasibility of realizing functionally graded structures consisting of two different materials (i.e., a functional and a structural material). Compression specimens consisting of the processed shape memory alloy and the austenitic build platform in equal parts were investigated. The microstructure was analyzed in the ...
Aufsatz
Effects of blending poly(lactic acid) and thermoplastic polyester polyurethanes on the mechanical and adhesive properties in two-component injection molding
(2022-09-16)
One possible way to increase the use of bioplastics and thus contribute to a more resource-efficient and sustainable economy is to broaden the application range of such bioplastics. Poly(lactic acid) (PLA) is a promising and commercially available bio-based and biologically degradable polymer, which exhibits a high strength and stiffness but is very brittle. Blending with other polymers can lead to an enhancement of the ductility of the PLA. The goal of this work was to show that blending of PLA with a bio-based ...
Aufsatz
Modification of self-reinforced composites (SRCs) via film stacking process
(2022-02-25)
This work presents the mechanical behavior of self-reinforced composites (SRCs) manufactured and modified via film stacking. For modification, interleaved films made of polypropylene (PP), a thermoplastic elastomer and a polyolefin engage were combined in different ways to induce the elastic modifier into the matrix material. The content of modifier was also varied in two ways. First, the films were produced out of a single material and second out of a compound. So, the same content of modifier was implemented in two ...
Aufsatz
Influences on the mechanical properties of SRCs in a combined compacting and back injecting process
(2022-03-03)
In this research paper, the effects of the combined compacting and back-injection process to produce back-injected self-reinforced composites on the mechanical properties of the self-reinforced composites (SRCs) are investigated. For this purpose, the parameters barrel temperature, time of injection and holding pressure were varied for the back injection. Tensile and bending tests were carried out on the SRCs. The results show that the mechanical properties depend to a large extent on the process parameters. The ...