Refine
Document Type
- Article (1)
- Part of a Book (1)
- conference proceeding (article) (1)
Has Fulltext
- no (3)
Is part of the Bibliography
- no (3)
Keywords
Institute
- Fakultät Angewandte Natur- und Kulturwissenschaften (1)
- Fakultät Maschinenbau (1)
- Fakultät Sozial- und Gesundheitswissenschaften (1)
- Institut für Sozialforschung und Technikfolgenabschätzung (IST) (1)
- Labor Additive and Intelligent Manufacturing for Sustainability (AIMS) (1)
- Labor Empirische Sozialforschung (1)
- Labor Nanoanalytik und Halbleiterchemie (Nanochem) (1)
Begutachtungsstatus
- peer-reviewed (1)
We used ultrafast electron diffraction and density-functional theory calculations to gain insight into the charge density wave (CDW) formation on In/Si(111). Weak excitation by a femtosecond-laser pulse results in the melting of the CDW. The immediate freezing is hindered by a barrier for the motion of atoms during the phase transition: The melted CDW constitutes a long-lived, supercooled phase and is strong evidence for a first-order transition. The freezing into the CDW is triggered by preexisting adsorbates. Starting at these condensation nuclei, the CDW expands one dimensionally on the In/Si(111) surface, with a constant velocity of more than 80 m/s.
The use of thermoplastics in lightweight construction is continuing to grow. This implies the need for suitable joining techniques to combine thermoplastics with other materials, such as metals, to gain tailored multi-material parts. In this paper latest results of experimental investigations on laser-based hot-melt bonding and injection molding for laser-structured metal plastic hybrids are presented. As materials stainless steel and short-fiber reinforced polyamide are used. The stainless steel surface is structured with a nanosecond pulse laser before joining to improve the mechanical adhesion between the dissimilar materials. Thereby, different structure depths in the range between 16.6 ± 1.2 µm and 66.5 ± 2.5 µm as well as different hatch distances between 70 and 300 µm are realized. The laser-based joining process is carried out irradiating the metallic surface multiple times. Positioned below the metal in T-joint configuration, the thermoplastic melts as a result of heat transfer and acts as hot-melt cohesive. Besides, hybrid joints are manufactured using injection molding. For experiments, the mold temperature as well as the melt temperature are varied. Regardless of the joining process, the hybrid joints are mechanically characterized by tensile tests. The results demonstrate that for both joining processes strong laser-structured metal plastic hybrids can be realized.