Radel, Tim
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Item-typ:Veröffentlichung, Laserstrahlschweißen von Aluminiumlegierungen mit Schwingungsüberlagerung(2020-01-24); ; ; Eine Schwingungsüberlagerung wurde beim Laserstrahlschweißen von Aluminium verwendet, um die Nahteigenschaften durch ein feinkörnigeres Gefüge zu verbessern und die Heißrissanfälligkeit zu vermindern.DissertationBand:0069749 1069 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Macro-pore free sub-surface PBF-LB/M components through laser polishingDespite notable improvements in the laser-based powder bed fusion of metals (PBF-LB/M) in recent years, residual porosity is still an issue. Near surface pores can affect the functional properties of PBF components, such as their fatigue life, yield strength, or corrosion behavior. To help address the challenge, this work shows that laser polishing decreases the surface roughness while also creating a highly dense sub-surface region of PBF parts with only microscale pores remaining.Wissenschaftlicher Artikel279 259 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, On the combination of plasma nitrided surfaces and LIPSS(BIAS Verlag, 2022-11); ; ; ; LIPSS are subjected to excessive wear when exposed to direct contact in tribological applications. Therefore, precautions must be taken to increase LIPSS’ hardness and wear resistance while simultaneously preserving their properties like superhydrophilicity. This work shows that a firstly plasma nitrided and subsequently structured surface results in LIPSS of high nano-hardness (14.88 GPa ± 1.05 GPa) who show a super hydrophilic wetting behavior (contact angle of 7°). The results indicate that a previous nitriding could bring LIPSS into tribological applications.Wissenschaftlicher Artikel244 161 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Tensile strength of Nitinol flanges fabricated by laser rod end melting and immediate flange processingNitinol is a shape memory alloy used for actuator applications. However, the connection between Nitinol wire and mechanical system via adhesive bonding or crimping could be weakened due to the exposure of joint in aggressive environments and temperature changes. Therefore, a process chain called laser rod end melting with immediate flange processing has been put forward and proven to fabricate all-in-one Nitinol flanges. According to previous work, there is a partially solidified preform connecting to the wire as the shaft, where the connection factures under tensile tests. In the present study, the effect of size of partially solidified preform on the tensile behavior was investigated on the cylindrical flanges with different flange heights. The results show that the partial preform volume increases with the flange heights, while the tensile strength becomes smaller when the flange height is too small. This suggests that it is important to maintain the mechanical strength of Nitinol flange by choosing the appropriate flange height.Wissenschaftlicher Artikel264 118 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Materials Characterization at High Strain RatesThe identification of material properties at high strain rates is of considerable technical interest, e.g., in applications for passenger safety-related parts which are expected to absorb energy in case of collisions. To additionally meet the requirements of a rapid and resource-efficient materials characterization, a novel highspeed hardness testing method based on laser-induced shock waves was investigated. The principal applicability of this laser-induced shockwave indentation technique for materials characterization at high strain rates is shown.Wissenschaftlicher Artikel284 179 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Influence of electrolyte concentration on laser chemical machiningTo meet the increasing trend of miniaturization, new (non-conventional) manufacturing processes are constantly being developed. The laser chemical process describes one of these non-conventional removal process in the microscale, based on the thermochemical dissolution of metals. To determine the influence of electrolyte concentrations, linear cavities were created in Titanium Grade 1 using phosphoric acid and sulfuric acid with different concentrations. The experimental results show that as the electrolyte concentration increases, the process window is reduced. One possibility for this is, as the electrolyte concentration increases, the viscosity increases, as well. With increasing viscosity, the electrolyte boiling process, which causes the shielding effect of the gas bubbles becomes more significant. Due to the increasing conductivity of the electrolyte at higher concentrations, the laser chemical removal rate increases within the process window at constant laser power. The maximum removal rate is observed at the maximum conductivity of the electrolyte.Wissenschaftlicher Artikel243 173