<p class="AMSmaintext">The goal of the present work is to evaluate mechanical properties and to analyse the microstructure of 316L stainless steel produced by Laser Powder Bed Fusion (L-PBF) follow by rolling with different thickness reduction under ambient and cryogenic conditions. The samples before rolling were heat treated. The static tensile test was realized at ambient and cryogenic (77K) conditions. The L-PBF powder metal production technology approved that is a key technology in the AM area, especially for metal powder materials. Mechanical properties tested at 298K and 77K shows that the application of various thermo-deformation rolling conditions increases of strength properties. Achieved mechanical properties are comparable to conventional bulk materials. The strength properties after the rolling under ambient and cryogenic conditions were significantly increased.<strong></strong></p>

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This experimental study focuses on the assessment of mineral additives and their incorporation into cement composites (CC). The assessment was based on a holistic approach to the performance of the durability properties of CC. Environmental suitability was also taken into consideration. In the experiments, cement pastes with w/c ratios of 0.3, 0.4, and 0.5, respectively, were prepared. Natural zeolite (NZ) and densified silica fume (SF) at doses of 7.5 and 15.0 wt.% of cement were used as the investigated (replacement) materials. Their effects (including development over time) on density, strength (flexural and compressive), porosity by water absorption, permeability by rapid chloride penetration (RCP) test, phase content by thermal analysis, and hydration progression, were observed. The results were then used to propose an evaluation approach. Natural zeolite was used for its known pozzolanic activity and classification as a supplementary cementitious material (SCM). In contrast SF acted as a filler in cement pastes, and thus did not have a direct positive effect on durability. The concept of comprehensive analysis for unknown additive classification is proposed to expressly differentiate between SCM, inert, and improving mineral additive. This concept could be applied to the assessment of mineral additives with regards to the durability and suitability of cement composites.

Additive manufacturing, including laser powder bed fusion, offers possibilities for the production of materials with properties comparable to conventional technologies. The main aim of this paper is to describe the specific microstructure of 316L stainless steel prepared using additive manufacturing. The as-built state and the material after heat treatment (solution annealing at 1050 °C and 60 min soaking time, followed by artificial aging at 700 °C and 3000 min soaking time) were analyzed. A static tensile test at ambient temperature, 77 K, and 8 K was performed to evaluate the mechanical properties. The characteristics of the specific microstructure were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The stainless steel 316L prepared using laser powder bed fusion consisted of a hierarchical austenitic microstructure, with a grain size of 25 µm as-built up to 35 µm after heat treatment. The grains predominantly contained fine 300–700 nm subgrains with a cellular structure. It was concluded that after the selected heat treatment there was a significant reduction in dislocations. An increase in precipitates was observed after heat treatment, from the original amount of approximately 20 nm to 150 nm.

Non grain oriented isotropic electrical steels, commercially called NGOES, were investigated in cryogenic temperature conditions. At cryogenic temperatures plastic deformations form strong structural heterogeneities in the sample thickness. Samples processed by cryo rolling show a bigger storage energy. To achieve abnormal grain growth through the process of static recrystallization, the annealing conditions were applied to the deformed samples. Moreover, minimal magnetic losses were reached when mean grain size diameter was approximately 150 µm.