Investigation on the Microstructure Hardness for the Hot Compressed Duplex Steel

Effect of microstructure size and type on the hardness for the duplex steel were disclosed by using of optical microscope (OM), scanning electron microscope (SEM) and nanoindenter for the samples hot compressed under different temperature with reduction of 10%, 30%, 50% and 70%. OM and SEM were used to measure the average martensite lamellar width, space and indenter morphology. nanoindenter test characterized the microstructure hardness for the samples under different process. Experiment results show that martensite hardness for the sample hot compressed at 950°C has larger diversity than that of sample hot compressed at 1200°C. The martensite hardness fluctuation range for the sample compressed at 950°C is almost from about 7GPa to 12GPa, while, for the sample compressed at 1200°C, the fluctuation range is basically from about 9GPa to 12GPa. However, the average hardness for the samples hot compressed at 950°C is comparably smaller, which is related with lower quench temperature. The larger martensite hardness fluctuation is mainly related with induced ferrite formation and finer martensite lamellar width. For the ferrite phase, the hardness fluctuation range is lower.

Kinetic study of lithium-zinc ferrite synthesis under electron beam heating

The paper considers kinetic studies lithium-zinc ferrite synthesis under heating by high-energy electron beam of mixtures of the initial Fe2O3 – Li2CO3 – ZnO reagents of different prehistory. We used samples of bulk density and compressed in hydraulic press. Radiation-thermal synthesis of samples was carried out an ILU-6 pulsed electron accelerator by heating of high-energy electrons with 2.4 MeV energy. Was spending heating to 600, 700, 750 °C and kept at 0 to 120 minutes. Formation of ferrite in conventional thermal annealing at similar temperature and time conditions was studied for comparison. Characterized method for studying synthesized samples was X-ray diffraction analysis. It is found that the rate of ferrite formation depends on both the heating method and the density of the initial mixture. It is shown that heating the mixture with an electron beam significantly accelerates the process of obtaining ferrite, which is manifested in a decrease of the kinetic parameters of ferrite synthesis. The increase the rate of ferrite formation under high-energy electron irradiation is due to a significant decrease in activation energy of synthesis process and decrease in pre-exponential multiplier in temperature dependence.