International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The paper deals with the problem of occurrence of internal defects in materials produced by SLM technology. The influence of the position of materials on the platform during the SLM on selected properties – porosity and corrosion resistance were examined. The reuse of non-compacted powder (three times recycled powder) and its effect on porosity and corrosion resistance of materials was also tested. Porosity was measured on metallographic sections in two perpendicular directions by image analysis, corrosion properties were tested by linear polarization method.

The effect of the low-frequency vibration processing on the residual elastic stresses in the Ti-6Al-4V alloy manufactured by 3D printing (Selective laser melting) was investigated. The studied sample was manufactured horizontally in respect to the building platform. Different vibration oscillations modes (vertical, horizontal, and elliptical) were chosen for study. The oscillations were done with frequency of 16 Hz, and a processing time was 20 minutes. Studies shown that 3D printed sample had a high level of residual elastic stresses, which were changed after vibration treatment. The optimal parameters of vibration processing, which provide a minimum level of residual elastic stresses in 3D printed Ti-6Al-4V alloy are discussed.

The application of the selective laser melting (SLM) method requires knowledge of not only the properties of the material after manufacturing, but also after mechanical loading. The aim of this work is to investigate the strain-rate dependence and microstructure of Ti6Al4V samples manufactured by SLM method with different angles to the building platform. SLM Ti-6Al-4V samples were manufactured using the EOSINT M280 (EOS GmbH) at angles of 0°, 30°, 45°, 90° to the building platform. A medicine Ti6Al4V (ASTM grade 23) powder was used for the study. Tensile tests were performed with an Instron test machine using two strain rates 0.5 mm/min and 2 mm/min at room temperature. It was found the strain-rate dependence in the studied samples. The features of the mechanisms of hardening and softening in an investigated SLM Ti-6Al-V alloy are discussed.

TiAl6V (ELI) has the low density, low elastic modulus and high strength. Biocompatibility of this material allows one to adapt it to human implant production and successfully use in the manufacture of surgical implants. Spherical argon-atomized Ti6Al4V (ELI) (45µm) powder from TLS Technik was used for study. The chemical composition complies with the ASTM F-136 (grade 5), ASTM B348 (grade 23) standard for surgical implant applications. Two machines from two scientific centers (Russia and South Africa) were used for the manufacturing of the alloys. Analysis of the oxygen and nitrogen contamination in SLM alloys was done with Van de Graaff accelerator with 2 Mega Volts. It is found that the oxygen concentration in both samples is about 0.2 wt. % and decreases with the increasing of the sample depth; the nitrogen concentration is about 0,02 wt%. X-Ray results show an absence of beta (BCC) phase in both samples. TEM studies found the metastable martensitic structure and silicon nitride Si3N4.