Coupled role of alloying and manufacturing on deep cryogenic treatment performance on high-alloyed ferrous alloys

This study focuses on influence of alloying content and type of manufacturing on the effectiveness of deep cryogenic treatment (DCT) on properties of selected high-alloyed ferrous alloys (HAFA): EN HS6-5-2, EN HS6-5-2-5, EN HS6-5-3 and EN HS12-1-4. In order to evaluate the dependency of DCT performance on chemical composition and manufacturing type, the microstructure, hardness, impact and fracture toughness and fatigue properties were analyzed. Additionally, the fatigue data was evaluated using an adapted strain-life model in order to understand the unique effects of DCT with selected factors and provide a model for estimating the fatigue limit of DCT HAFA. The study indicates that DCT affects carbide precipitation, size and morphology of nanocarbides, average distance between carbides and nanocarbides, as well as the base matrix (martensitic laths). The induced microstructural changes cause an overall positive change of mechanical properties in selected HAFA, which correlates well with individual alloying and manufacturing differences. Overall, DCT has greater effect on wrought HAFA than powder metallurgy manufactured HAFA, at which high content of W and Co generally degenerates the DCT induced microstructure modifications

Evolution of microstructure during hot deformation of INCONEL 625 alloy with different strain rates

Hot compressions tests of Inconel 625 superalloy were conducted using a deformation dilatometer to the strain level of 0,7 at 1 050 °C, with a different strain rate. Optical microscope and electron backscatter diffraction technique were used to investigate the microstructure evolution and nucleation mechanisms of dynamic recrystallization. Microstructural evolution of Inconel 625, deformed to the strain level of 0,7 at 1 050 °C, reveals that the size of the dynamic recrystallization (DRX) grains and the fraction of DRX increase with the decrease in strain rate. At the strain rate 10 s-1, the grain sizes are mainly located in the size below 20 μm, indicating that nucleation of DRX was dominant due to the combined effects of high stored energy and short deformation time for grain growth at high strain rate

Evolution of microstructure during hot deformation of INCONEL 625 alloy with different strain rates

Hot compressions tests of Inconel 625 superalloy were conducted using a deformation dilatometer to the strain level of 0,7 at 1 050 °C, with a different strain rate. Optical microscope and electron backscatter diffraction technique were used to investigate the microstructure evolution and nucleation mechanisms of dynamic recrystallization. Microstructural evolution of Inconel 625, deformed to the strain level of 0,7 at 1 050 °C, reveals that the size of the dynamic recrystallization (DRX) grains and the fraction of DRX increase with the decrease in strain rate. At the strain rate 10 s-1, the grain sizes are mainly located in the size below 20 μm, indicating that nucleation of DRX was dominant due to the combined effects of high stored energy and short deformation time for grain growth at high strain rate