Mid Sweden University

Metal additive manufacturing (AM) is on its way to industrialization. One of the most promising techniques within this field, electron beam melting (EBM), is nowadays used mostly for the fabrication of high‐performance Ti‐based alloy components for the aerospace and medical industry. Among the industrial applications envisioned for the future of EBM, the fabrication of high carbon steels for the tooling industry is of great interest. In this context, the process windows for dense and crack‐free specimens for a highly alloyed (Cr–Mo–V) cold‐work steel powder are presented in this article. High‐solidification rates during EBM processing lead to very fine and homogeneous microstructures. The influence of process parameters on the resulting microstructure and the chemical composition is investigated. In addition, preliminary results show very promising mechanical properties regarding the as‐built and heat‐treated microstructure of the obtained material.

Storage of snow has become of increasing interest for the winter business industry. Covering a pile of snow with an insulating material protects the snow from heat transfer from the surroundings and reduces the melting. Storing snow enables ski resorts to set an opening date, and it can also be used to secure winter sports events that are dependent on snow. Cover materials that are commonly used as insulation are wood-based materials, such as sawdust, and textile materials and sheets. How efficiently a cover material functions as thermal insulation depends on the material characteristics and thickness of the insulating layer. In this study, results from a laboratory experiment are presented, which aimed at comparing different commonly used cover materials, as well as some other materials that have not previously been used as thermal insulation on snow. Different layer thicknesses were also investigated. The results show that the insulating capacity of sawdust is reduced with time. Despite degrading insulating properties with time, sawdust is still considered one of the best materials to use as insulation on snow, and it is also more efficient than the textile materials investigated in this study. Doubling the textile layers or adding a three-dimensional (3D) spacer textile, which implies adding a layer of air between the textile and the snow, reduces the snow melting. Water absorption, water transport, and evaporation of water affect the melting. In this work, evaporative cooling did not prove to reduce melting; therefore, it was not evident whether a textile material should be permeable. An interesting material used in the study was Quartzene, which absorbed all the melt water and protected the snow most efficiently of the materials tested. 

Custom orthopedic and dental implants may be fabricated by additive manufacturing (AM), for example using electron beam melting technology. This study is focused on the modification of the surface of Ti6Al4V alloy coin-like scaffolds fabricated via AM technology (EBM®) by radio frequency (RF) magnetron sputter deposition of hydroxyapatite (HA) coating. The scaffolds with HA coating were characterized by Scanning Electron microscopy, X-ray diffraction. HA coating showed a nanocrystalline structure with the crystallites of an average size of 32±9 nm. The ability of the surface to support adhesion and the proliferation of human mesenchymal stem cells was studied using biological short-term tests in vitro. In according to in vitro assessment, thin HA coating stimulated the attachment and proliferation of cells. Human mesenchymal stem cells cultured on the HA-coated scaffold also formed mineralized nodules.

Present paper reports on the results of surface modification of the additively manufactured porous Ti6Al4V scaffolds. Radio frequency (RF) magnetron sputtering was used to modify the surface of the alloy via deposition of the biocompatible hydroxyapatite (HA) coating. The surface morphology, chemical and phase composition of the HA-coated alloy were studied. It was revealed that RF magnetron sputtering allows preparing a homogeneous HA coating onto the entire surface of scaffolds.