@article{DobbelsteinGeorgeGurevichetal.2021,
  author    = {Dobbelstein, Henrik and George, Easo P and Gurevich, Evgeny L and Kostka, Aleksander and Ostendorf, Andreas and Laplanche, Guillaume},
  title     = {Laser metal deposition of refractory high-entropy alloys for high-throughput synthesis and structure-property characterization},
  series = {International Journal of Extreme Manufacturing},
  volume    = {3},
  journal   = {International Journal of Extreme Manufacturing},
  number    = {1},
  publisher = {IOP Publishing},
  pages     = {015201 -- 015201},
  year      = {2021},
  abstract  = {Progress in materials development is often paced by the time required to produce and evaluate a large number of alloys with different chemical compositions. This applies especially to refractory high-entropy alloys (RHEAs), which are difficult to synthesize and process by conventional methods. To evaluate a possible way to accelerate the process, high-throughput laser metal deposition was used in this work to prepare a quinary RHEA, TiZrNbHfTa, as well as its quaternary and ternary subsystems by in-situ alloying of elemental powders. Compositionally graded variants of the quinary RHEA were also analyzed. Our results show that the influence of various parameters such as powder shape and purity, alloy composition, and especially the solidification range, on the processability, microstructure, porosity, and mechanical properties can be investigated rapidly. The strength of these alloys was mainly affected by the oxygen and nitrogen contents of the starting powders, while substitutional solid solution strengthening played a minor role.},
  language  = {en}
}
@article{WangNettGurevichetal.2021,
  author    = {Wang, Hao and Nett, Ralf and Gurevich, Evgeny L and Ostendorf, Andreas},
  title     = {The Effect of Laser Nitriding on Surface Characteristics and Wear Resistance of NiTi Alloy with Low Power Fiber Laser},
  series = {Applied Sciences},
  volume    = {11},
  journal   = {Applied Sciences},
  number    = {2},
  doi       = {10.3390/app11020515},
  pages     = {515},
  year      = {2021},
  abstract  = {The laser nitriding was performed in nitrogen gas at room temperature (20 °C) and low temperature (-190 °C) by a low power fiber laser to modify the wear and abrasion resistance of NiTi alloy. The surface roughness and element composition were analyzed by roughness device and energy-dispersive X-ray spectroscopy respectively. The results of roughness show that laser treatment can change the surface roughness due to the laser remelting. The effect of laser nitriding on the microhardness, friction coefficient, and worn scars of NiTi alloy was also studied, which shows that the microhardness of the NiTi alloy increases after laser nitriding. The optical microscope and scanning electron microscope were used to characterize the surface of NiTi alloy after wear testing to observe the microstructure of worn scars. The results show that the laser nitriding with different parameters can induce a nitride layer with different thicknesses and the higher energy deposition is the key factor for the formation of the nitride layer, which can decrease the friction coefficient and reduce wear loss during the application of NiTi alloy. The improvement of wear resistance can be attributed to the hard nitriding layer.},
  language  = {en}
}
@article{KasischkeHartmannNiermannetal.2021,
  author    = {Kasischke, Maren and Hartmann, Simon and Niermann, Kevin and Kostyrin, Denis and Thiele, Uwe and Gurevich, Evgeny L},
  title     = {Pattern Formation in Slot-Die Coating},
  series = {arXiv.org},
  volume    = {2021},
  journal   = {arXiv.org},
  pages     = {1 -- 24},
  year      = {2021},
  abstract  = {We experimentally study the occurrence of pattern formation during the slot-die coating of low-viscosity nearly Newtonian liquids onto Polyethylenterephthalat (PET)-substrates. In particular, it is demonstrated that with increase of the coating speed a homogeneous coating becomes unstable with respect to periodic stripe patterns. Thereby, depending on the liquid viscosity, the stripes can be oriented parallel or perpendicular with respect to the coating direction. Mixed states do also occur. The spatial period of perpendicular [parallel] stripes increases [decrease] with the coating speed. The dependence of the effect on various control parameters of slot-die coating is investigated. Finally, a simple theoretical model based on the hydrodynamics of thin films of partially wetting liquids is analysed. Comparing the results to the experiments, conclusions are drawn regarding the acting instability and pattern formation mechanisms.},
  language  = {en}
}
@inproceedings{WangGurevichOstendorf2021,
  author    = {Wang, Hao and Gurevich, Evgeny L and Ostendorf, Andreas},
  title     = {Application of nanoindentation technique to test surface hardness and residual stress of NiTi alloy after femtosecond laser shock peening},
  series = {High-Power Laser Materials Processing: Applications, Diagnostics, and Systems X / SPIE.Digital.Library},
  booktitle = {High-Power Laser Materials Processing: Applications, Diagnostics, and Systems X / SPIE.Digital.Library},
  publisher = {International Society for Optics and Photonics},
  address   = {USA},
  doi       = {10.1117/12.2593092},
  pages     = {116790J-0 -- 116790J-5},
  year      = {2021},
  abstract  = {Laser shock peening is a new and important surface treatment technique that can enhance the mechanical properties of metal materials. Normally, the nanosecond laser with pulse-width between 5 ns and 20 ns is used to induce a high-pressure shock wave that can generate plastic deformation in the top layer of metals. The femtosecond laser shock peening in the air has been studied recently, which can induce higher pressure shock wave than that of traditional nanosecond laser shock peening in a very short time. The NiTi alloy is processed by femtosecond laser shock peening, then a nanoindentation device is used to measure its surface hardness and residual stress. The hardness results of NiTi alloy before and after treatment show that the femtosecond laser shock peening can increase the hardness of NiTi alloy, which also shows that the femtosecond laser can be used to perform laser shock peening on NiTi alloy without coating.},
  language  = {en}
}