No abstract

Micro-nano hierarchical structure on the substrate was fabricated by a hybrid approach including laser deposition, laser ablation and chemical dealloying. The structure consists of micro bumps with a width of 50 μm and a height of 100 μm, and nanoporous structures with a size of 70-150 nm on the micro bumps. XRD and XPS results confirm that these hierarchical structures were made of Cu(2)O. For use in comparison, three additional structures with feature size in milliscale, microscale, and nanoscale were also prepared respectively by the proposed methods. Under visible light, the micro-nano structure exhibited the best performance of photodegradation. It is the result of the large specific surface and the catalytic reaction driven by the cuprous oxides.

Laser Additive Manufacturinglaser metal Deposition (lmD) and selective laser melting (slm) in turbo-engine applications Andres gAsser andres gasser studied applied physics at the technical University of Darmstadt, germany, where he received his diploma degree in 1985. since then he has been working in the field of surface treatment at the Fraunhofer ilt. He received his phD thesis in mechanical engineering in 1993. He has led many national and international projects in the field of optics, process development and system engineering and has implemented several lmD machines at companies like Braun gmbH, stork gears&services and rollsroyce germany. actually he is the speaker of the lmD group at the ilt, in charge of the lmD system components and project leader of the innovation cluster turpro at the ilt.

Selective laser melting (SLM), due to its unique additive manufacturing processing philosophy, demonstrates a high potential in producing bulk-form nanocomposites with novel nanostructures and enhanced properties. In this study, the nanoscale TiC particle reinforced AlSi10Mg nanocomposite parts were produced by SLM process. The influence of “laser energy per unit length” (LEPUL) on densification behavior, microstructural evolution, and wear property of SLM-processed nanocomposites was studied. It showed that using an insufficient LEPUL of 250 J/m lowered the SLM densification due to the balling effect and the formation of residual pores. The highest densification level (>98% theoretical density) was achieved for SLM-processed parts processed at the LEPUL of 700 J/m. The TiC reinforcement in SLM-processed parts experienced a structural change from the standard nanoscale particle morphology (the average size 75–92 nm) to the relatively coarsened submicron structure (the mean particle size 161 nm) as the applied LEPUL increased. The nanostructured TiC reinforcement was generally maintained within a wide range of LEPUL from 250 to 700 J/m and the dispersion state of nanoscale TiC reinforcement was homogenized with increasing LEPUL. The sufficiently high densification rate combined with the uniform distribution of nanoscale TiC reinforcement throughout the matrix led to the considerably low coefficient of friction of 0.38 and wear rate of 2.76 × 10−5 mm3 N−1 m−1 for SLM-processed nanocomposites at 700 J/m. Both the insufficient SLM densification response at a relatively low LEPUL of 250 J/m and the disappearance of nanoscale reinforcement at a high LEPUL of 1000 J/m lowered the wear performance of SLM-processed nanocomposite parts.