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Konferenzveröffentlichung
The Influence of different die geometries on the Extrusion Process of High-Consistency Silicone Rubber
(Society of Plastics Engineers, 2019)
Silicone Rubber and especially High-Consistency Silicone Rubber (=HCR), are typically processed in the extrusion process. Due to the high requirements in terms of the ma-terial properties and the geometric dimensions, a funda-mental knowledge of the whole process including experi-ences in tool design are essential.
In this study, HCR with different Shore-hardnesses are extruded on a vertical silicone extrusion line with various breaker plates with different length to diameter ratios (=L/D-ratio) in order to analyze ...
Konferenzveröffentlichung
Natural fiber reinforced technical (bio-) composites modified with halogen-free flame retardants
(Society of Plastics Engineers, 2019)
Under the aspect of sustainability and the use of alternative materials, engineering thermoplastics such as polybutylene terephthalate (PBT) will be reinforced with renewable raw materials such as regenerated cellulose fibers.
The University of Kassel is developing cellulose regenerated fiber reinforced technical thermoplastics in a state-funded project with further companies. Since pure natural fibers cannot withstand the high operating temperature of engineering thermoplastics (Ts>230°C), regenerated cellulose ...
Konferenzveröffentlichung
Blending CA with PBS to increase the bonding strength in two-component injection molding
(Society of Plastics Engineers, 2019)
Since CA shows no adhesive properties in the two-component injection molding process with bio based TPU, blends of CA and PBS were produced to decrease the interfacial tension between the materials. While the interfacial tension was calculated from the results of a drop shape analysis, the adhesion strength was measured in peel tests according to the guideline VDI 2019. The comparison of the results gave information about whether the drop shape analysis is a valid method to analyze the adhesive characteristics of ...
Konferenzveröffentlichung
Flexible Foams made of Liquid Silicone Rubber and expandable Microspheres
(2019-10-02)
In this study, the possibility of foaming liquid silicone rubber (LSR) was investigated. The foam was produced by injection molding with two different thermoplastic, expandable microspheres. Different properties were tested using the S2-tensile bar, e.g. density, tensile strength, specific tensile strength, elongation at break, stress at 100 % strain and the hardness. It was found that the two types of microspheres used have similar effects on density, specific tensile strength and elongation at break, but differ in ...
Aufsatz
Processing effects on tensile superelastic behaviour of Fe43.5Mn34Al15 ± XNi7.5∓X shape memory alloys
(2019)
Fe₄₃.₅Mn₃₄Al₁₅Ni₇.₅ was introduced in the current decade as a new superelastic alloy with great applicative potential due to: (i) superelastic behaviour over a thermal range of 200°C and (ii) recoverable strains up to 9.7 %. One of the key factors in enhancing the superelastic response of several shape memory alloys (SMAs) is the formation of an oligocrystalline structure, i.e. without triple junctions between grains, which is the result of an abnormal grain growth (AGG) process that can be induced by cyclic heat ...
Aufsatz
Shape memory effect and superelasticity in high-strength FeNiCoAlTi single crystals hardened by nanoparticles
(2019-11-19)
For [001]-oriented single crystals of Fe-28Ni-17Co-11.5Al-2.5Ti (at %) alloy in tension, it was shown that particles of the γ’-phase with a size of 4–6 nm lead to the appearance of superelasticity, with a strain of εSE=4.5% and a shape memory effect of εSME=5.9%. Increasing the particle size to 10–12 nm reduces εSE to 3.6% and εSME to 3.5%. The paper discusses the causes of the influence of particle size on the reversible strain.
Aufsatz
Promoting abnormal grain growth in Fe-based shape memory alloys through compositional adjustments
(2019-05-28)
Iron-based shape memory alloys are promising candidates for large-scale structural applications due to their cost efficiency and the possibility of using conventional processing routes from the steel industry. However, recently developed alloy systems like Fe–Mn–Al–Ni suffer from low recoverability if the grains do not completely cover the sample cross-section. To overcome this issue, here we show that small amounts of titanium added to Fe–Mn–Al–Ni significantly enhance abnormal grain growth due to a considerable ...
Aufsatz
Cyclic Deformation Response of Ultra-fine Grained Titanium at Elevated Temperatures
(2019)
This study focuses on the high-temperature cyclic deformation response (CDR) of ultra-fine grained (UFG) titanium of commercial purity (grade 4) processed via equal channel angular extrusion as a severe plastic deformation method. Low-cycle fatigue experiments were conducted at elevated temperatures up to 600 °C and at strain amplitudes ranging from 0.2% to 0.6%. Besides temperature and strain amplitude, the influence of two processing routes (8BC and 8E) on the fatigue characteristics of UFG Ti was examined. It is ...