AISI 316L stainless steel (SS) is one of the extensively used biomaterials to produce implants and medical devices. It provides a low-cost solution with ample mechanical properties, corrosion resistance, and biocompatibility compared to its counterpart materials. However, the implants made of this material are subjected to a short life span in human physiological conditions leading to the leaching of metal ions, thus limiting its use as a biomaterial. In this research, the addition of boron, titanium, and niobium with varying concentrations in the SS matrix has been explored. This paper explores the impact of material composition on modified SS alloy’s physical and mechanical properties. The study’s outcomes specify that the microhardness increases for all the alloy compositions, with a maximum increase of 64.68% for the 2 wt.% niobium added SS alloy. On the other hand, the tensile strength decreased to 297.40 MPa for the alloy containing 0.25 wt.% boron and 2 wt.% titanium additions compared to a tensile strength of 572.50 MPa for pure SS. The compression strength increased from 776 MPa for pure SS to 1408 MPa for the alloy containing niobium and titanium additions in equal concentrations.

This article deals with a new original analytical solution of deformation, force and stress states in wood screw joints up to the limit values of pulling out/breaking the screw. The screws are under tension. The wood-to-screw interaction is effectively simplified by introducing several physical model variants using a tangential elastic non-linear foundation. The experimental verification of the proposed models using pull-out tests (i.e., pulling out screws from dry spruce wood in laboratory conditions) confirms the correctness of the proposed models of the elastic linear/non-linear foundation. The validity of the model is also analytically and experimentally verified in the biomechanical model of pulling out screws from the femur of a bovine/human cadaver, which confirms and expands the validity of newly designed screw joint models outside the timber structure area.

This study investigates how machining parameters affect surface integrity and fatigue performance in 42CrMo4 + QT steel. Nine turning setups were tested to evaluate surface roughness, residual stresses, and fatigue strength. Fatigue testing under fully reversed loading (R = –1) at ∼150 Hz revealed that the best fatigue performance occurred in the setup with a cutting speed of 100 m/min, feed rate of 0.1 mm/min, tool nose radius of 0.4 mm, 0.3 mm total finishing depth (over three cuts), and coolant applied. Cutting speed showed the clearest benefit, while other parameters had less predictable effects. Surface roughness did not consistently correlate with fatigue life. Overall, selected machining parameters strongly influence fatigue behavior, though roughness and residual stresses alone do not fully explain the performance trends observed.

This article focuses on a type of surgical implant used in orthopaedics and traumatology—cannulated femoral nails. Femoral nails are used in medical treatment for purposes of osteosynthesis, i.e., when treating various types of complicated fractures, in this case fractures of the femur. The article investigates cases in which a nail has been implanted in the proximal part of the femur for a short time (with the fracture still not healed), compared with cases in which the bone has already healed. According to AO classification, examined fractures are described as AO 31B3 AO 32A3. The main focus is on strength-deformation analysis using the finite element method (FEM), which makes it possible to determine the behaviour of the femur-implant system. FEM analysis was used to compare 1.4441 steel nails made by two manufacturers, Medin (Czech Republic) and Tantum (Germany). Boundary conditions including external loading, prescribed supports and elastic foundation are defined. There were solved FEM analyses for five cases of healed femur and five cases of broken femur both including implants with prescribed collo-diaphyseal angles. The results of the analysis were used to assess stress-deformation states from the perspective of appropriateness for clinical treatment, biomechanical reliability and safety. All examined femoral nails are compared, safe and suitable for patient treatment.

Additive Manufacturing (AM) has revolutionized modern production. However, its integration with conventional or subtractive manufacturing is still underexplored. Therefore, this study investigates the machinability of 316L stainless steel (SS) produced with rolling or Powder Bed Fusion – Laser Beam (PBF-LB) technologies under dry turning. Compared with rolled specimens, the AM samples exhibit greater variability in machining performance and higher sensitivity to cutting conditions. It is demonstrated from the results that sample with the highest feed shows the least favorable machinability. In particular, the PBF-LB specimen machined at the highest feed rate exhibits the highest cutting force and tool vibration, produces the roughest machined surface, and generates the highest cutting-zone temperature. It also shows relatively high flank wear and has the shortest tool life. Although the measured temperatures remain well below the melting point of 316L SS, optical microscopy reveals pronounced built-up edge formation, indicating that adhesive wear rather than thermal melting is the dominant wear mechanism. These findings demonstrate that rolled 316L provides more stable machining behavior and offer practical guidance for optimizing the dry turning of AM 316L SS.

Additive Manufacturing (AM) has revolutionized modern production. However, its integration with conventional or subtractive manufacturing remains underexplored. Therefore, this study investigates the machinability of 316L stainless steel (SS) produced by rolling and Powder Bed Fusion Laser Beam (PBF-LB) technologies under dry turning. The metrics investigated include cutting force, vibration, surface roughness, cutting-zone temperature, tool wear, and tool durability. Under the same experimental conditions, the PBF-LB samples exhibited greater variation in machining responses than the rolled samples. Among the tested conditions, the PBF-LB sample machined at the highest feed was associated with the highest cutting force (1351 N), highest cutting-zone temperature (477 °C), and shortest tool durability (60 s). The largest measured tool damage (4.12 mm), however, was observed for a different PBF-LB sample machined at a lower feed, with possible contribution of sample-to-sample variations in material and surface condition to tool wear. Optical microscopy on this sample revealed scratch-like marks and severe edge damage, which may be attributed to sliding and abrasive interactions. The observed differences in behavior between PBF-LB and rolled samples should be interpreted cautiously as independent sample replication and direct characterization of the tested materials were not performed. Overall, the results do not establish definitive statistical effects of manufacturing route but provide experimental observations of dry-turning behavior under a predefined set of cutting conditions, identifying sample variability and material characterization as considerations for future studies.