Low carbon low alloyed high strength steel with the chemical composition suitably designed to support the stabilization of retained austenite was used in this work. The steel was processed by conventional annealing for a reference and several different heat and thermomechanical treatments were further proposed to test typical TRIP (transformation induced plasticity), DP (dual phase) steel and QP (quenching and partitioning) processing routes. All the processing methods used the same soaking temperature of 1050 °C. Processed samples were subjected to metallographic analysis, hardness measurement and tensile test to characterise resulting microstructures. While simple annealing reached tensile strength of 861 MPa with 25% of total elongation, the best combination of the highest tensile strength of 903 MPa and a total elongation of 32% was obtained after processing typical for TRIP steel. QP treatment resulted in the highest tensile strength of 1289 MPa with a total elongation of 19%.TRIP steel DP steel QP treatment high strength steel

Low-carbon low-alloyed high strength steel 0.2C-1.5Al-0.5Si-2Mn-0.06Nb (in weight %) was forged into bars and annealed at 1050 °C with either 2-hour hold and furnace cooling to room temperature or with 20-min hold and controlled cooling by 1 °C/s. These various holds and coolings created two different initial microstructures, banded ferritic-pearlitic one for the long hold and bainitic-ferritic for the shorter hold and quicker cooling. Samples with those microstructures then underwent the same thermo-mechanical treatment (TMT) typical for TRIP (transformation induced plasticity) steels. Very different microstructures and mechanical properties were obtained for both initial states even after the application of the same TMT schedules. Light and scanning electron microscopy was used to characterize obtained microstructures and tensile tests were applied for the determination of mechanical properties.

Scanning electron microscopy (SEM) in the analysis of non-conductive samples became one of the most important methods for the investigation of material properties. In this work, we used SEM microstructure analysis for the investigation of the origin of cracks in granite composites and also, we tested the porosity inside the regenerated carbon biowaste, potentially used as a clean source of carbon for the future applications in materials production. Additionally, the morphology and the chemical composition of small particles used for the moulding processes of plastics were also tested. The importance of the microstructure investigation was supported by Energy-Dispersive X-ray Spectroscopy (EDS) often used for the chemical composition evaluation of these non-conductive materials.