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The purpose of this paper is to investigate the impact behaviour and damage characterization of carbon fibre reinforced aluminium hybrid laminates (Al/CFRP) in comparison to classic carbon fibre reinforced polymer (CFRP) at low-velocity and low-energy impact. Impact damage characteristic with damage initiation and progression, internal failure modes and understanding of the role of the metal layers in the impact behaviour under low-energy were examined and discussed. The damage mechanism of the tested laminates is very complex. There is an internal degradation of the material, with the plastic deformation in case of fibre metal laminates. Characteristic matrix cracks (bending and shearing cracks) running at the fibre–matrix interface in composite layers are the first damage mode. The critical damage mode is delaminations observed between composite layers with different orientation as well as delaminations at the metal–composite interface in fibre metal laminates. For the tested materials, particularly carbon fibre reinforced composites, the absorbed impact energy is mainly connected with elastic response and damage of the laminate. In case of fibre metal laminates the absorbed energy is also connected with plastic deformation of the laminate, occurring especially in the metal layers. High impact resistance of fibre metal laminates indicates that metal (aluminium) layers may prevent delamination propagation and impactor penetration.

The most popular prosthetic restorations are skeletal dentures. Clinical failures in the case of these prostheses are associated primarily with the accuracy and precision of the design, and laboratory procedures such as: melting and casting technique as well as the quantity of the once remelted alloy used for the batch. This article analyzes the impact of the amount of recycled material on the mechanical properties and structure of dental alloy CoCrMo. Vacuum casting method has been applied and alloys remelted with output compositions of 0, 25, 50, 75 and 100% of fine material. The static tensile test, microstructural analysis and SEM observation as well as macrohardness test have been conducted. It was observed that the mechanical strength of all remelted alloys is worse than the strength of the fine alloy. A heterogeneity increase in the structure of alloys with more recycled material was noticeable. Moreover, the occurrence of precipitates of various types of carbides and the presence of intermetallic phases which have a determining effect on the mechanical properties of received castings were noted.