Dariusz Grzesiak

Oxidation process of the steel/nc-TiC nanocomposites

Ceramic composites are widely used in various technologies such as tool production, aerospace technology, and nuclear power engineering. Their key features are considerable hardness and resistance to wear and corrosion at high temperature. Because many ceramic nanocomposites are designed to work at high temperature, it is important to determine their high temperature corrosion resistance. The subject of the investigation in this study were nanocomposite MMC (metal matrix composite) materials. As matrix the 316L stainless steel was used and the filler (nanoparticles) was nc-TiC. Using carbonized and purified nc-TiC particles the technology of the production of the nanocomposite structures based on the selective laser melting (SLM) technology was worked out. The MCP HEK Realizer II device was applied. The particles have been depicted by TEM method, whereas characterization of structure and particles size was performed by XRD method. The results of investigations on oxidation process of the steel/ncTiC nanocomposites in dry air have been presented. TG-DSC measurements were carried out under non-isothermal conditions at linear change of samples temperature in time and under isothermal conditions. MS method was used to determine evolved gaseous products.

Effect of milling time on thermal treatment of TiC, TiB2/steel powders

The results of investigation on influence of the milling process on mixed powders of nanocrystalline TiC and TiB2, obtained in non-hydrolytical sol–gel synthesis, and 316L stainless steel are presented. The powders have been used as substrates to prepare nanocomposite materials by Selective Laser Sintering/Melting process. In present work thermal analysis results along with the composition and structure of nanocrystalline powders have been presented. During investigation the following analytical techniques have been applied: XRD, TEM, TG-DSC-MS and SEM.

Mechanical Properties of Metal Matrix Nanocomposites Synthesized by Selective Laser Melting Measured by Depth Sensing Indentation Technique

This work presents an investigation of basic mechanical properties (hardness, Young modulus) of metal matrix composites (MMC) reinforced with non-oxide ceramic nanoparticles by means of nanoindentation measurements. The evaluated materials were manufactured by selective laser melting (SLS/M). As a matrix 316L stainless steel and as a reinforcing phase TiC nanoparticles were used. The influence of nanoscale reinforcement on the mechanical properties of MMC manufacturing with SLS/M process was examined. In this case statistical evaluation of hardness and Young modulus based on nanoindentation data was performed.

TECHNOLOGICAL PROBLEMS IN MACHINING OF RESILIENT WHEELSETS ON WHEEL-TURNING LATHES WITH FRICTION DRIVE

S u m m a r y Article presents attempt of identification of technological problems in machining of resilient wheelsets on wheel- turning lathes with friction drive. Main part of presented research was modelling of machined wheel using finite elements method in conditions of load with forces measured during machining of railway wheelsets. Presented research is a part of works performed in order to enable regeneration of tyre profiles of resilient wheelsets using wheel-turning lathes with friction drive, which are commonly used nowadays for machining heavy railway wheelsets.

Topology Optimisation Aimed at Additive—SLM Manufacturing of Metal Parts of ExoArm 7-DOF

Topology optimisation of mechatronic scanner arm components is presented in this chapter. Optimisation was carried out after static, linear FEM analysis of parts. Von Mises stress map was applied for topological optimisation (TO). Topological optimisation was performed by removal of body’s volumes. Optimised parts after removal remained partially perforated. Only functional areas of the parts remained unchanged. In order to fulfil outer part functional dimensions, cell lattice structures were applied. Cell structures were prepared in CAD/CAM system, fully parameterised. Boolean operations on optimised parts were applied to fill empty volumes. Parts were then generated with application of selective laser melting (SLM) technique. After SLM, machining of matching surfaces of corresponding elements was applied.

Selective Laser Melting of TiB2/H13 Steel Bulk Nanocomposites: Influence of Nanoscale Reinforcment

Additive Manufacturing (AM) holds strong potential for the formation of a new class of multifunctional nanocomposites. Selective laser melting, as a promising AM fabrication route, was applied to produce nanocrystalline TiB2-reinforced H13 steel matrix nanocomposites. Uniformly dispersed TiB2 particles were obtained and fine homogenous needle-shaped martensitic microstructures were observed. The microstructural and hardness of SLM-processed nanocomposites were sensitive to the TiB2 addition. Relative to the unreinforced H13 steel part, the TiB2/ H13 steel nanocomposites parts with the novel architecture exhibited much higher hardness due to the combined effects of grain refinements and grain boundary strengthening.

Microstructure and Tribocorrosion Properties of Titanium Matrix Nanocomposites Manufactured by Selective Laser Sintering/Melting Method

This work presents an investigation of tribocorrosion properties of titanium matrix composites (TMCs) reinforced with non-oxide ceramic nanoparticles. The evaluated materials were manufactured by selective laser melting technique (SLM). As a matrix titanium and as a reinforcing phase TiC nanoparticles were used. For SLM process the mixtures of the powders composed of 0, 1, 5, 10, and 20 vol % of nanocrysalline titanium carbide (nc-TiC) were prepared. The influence of the reinforcements on the tribocorrosion properties of TMCs manufactured by SLM process was examined. Tribocorrosion “ball on disc” tests in Ringers solution and under ambient dry conditions were carried out. It was shown that nanocomposite consisted of 20 vol.% of nc-TiC characterized by the best wear and tribocorrosion resistance.