The effects of solution treatment and annealing temperature on the microstructure and mechanical properties of a new TWIP steel that was alloyed from aluminum (Al), silicon (Si), vanadium (V), and molybdenum (Mo) elements were investigated by a variety of techniques such as microstructural characterization and room tensile testing. The austenite grain size grew slowly with the increase in annealing temperature. The relatively weak effect of the solution treatment and annealing temperature on the austenite grain size was attributed to the precipitation of MC and M2C, which hindered the growth of the austenite grain. The plasticity of the TWIP steel in cold rolling and annealing after solution treatment was obviously higher than that in cold rolling and annealing without solution treatment. This was because the large-size precipitates redissolved in the matrix after solution treatment, which were not retained in the subsequently annealed structure. Through cold rolling and annealing at 800 °C after solution treatment, the prepared steel exhibited excellent strength and plasticity simultaneously, with a yield strength of 877 MPa, a tensile strength of 1457 MPa, and an elongation of 46.1%. The strength improvement of the designed TWIP steel was mainly attributed to the grain refinement and precipitation strengthening.
Isothermal and non-isothermal pearlite transformations under 840°C warm-rolled and 950°C hot-rolled were researched. It was found that the pearlite nuclei at grain boundary and defects were increased by warm deformation. The results showed that the incubation time was shortened in the isothermal pearlite transformation and the volume fraction of pearlite was increased in continuous cooling condition by warm deformation. The pearlite transformation behaviour under continuous cooling condition was predicted by the formula of Umemoto. The critical cooling rates of the fully pearlite structures formed under warm deformation condition and hot deformation condition were calculated.
All inorganic lead halide cesium perovskite quantum dots(QDs) has attracted much attention due to its excellent luminescence properties, but further development is restricted by its stability and the existence of toxic element lead. In this paper, F/Mn- doped CsPb(Br/Cl) 3 QDs glass was prepared by melt quenching and heat treatment, it effectively reduces Pb content. The result shows that the spectrum of the quantum dot glass was adjustable between 450 nm to 515.4 nm by changing the feeding ratio of Mn-Pb ion and heat treatment temperature. Moreover, the introduction of Mn 2+ effectively improves the PLQY of CsPb(Br/Cl) 3 QDs glass and serves as a red-emitting. The prepared composites not only maintain good fluorescence characteristics, but also greatly improve the stability of quantum dots. Based on these advantages, the red-emitting perovskite quantum dot glass is expected to become a promising candidate for the high-power lighting material.
Abstract ：All inorganic lead halide cesium perovskite quantum dots(QDs) has attracted much attention due to its excellent luminescence properties, but further development is restricted by its stability and the existence of toxic element lead. In this paper, F/Mn- doped CsPb(Br/Cl) 3 QDs glass was prepared by melt quenching and heat treatment, it effectively reduces Pb content. The result shows that the spectrum of the quantum dot glass was adjustable between 450 nm to 515.4 nm by changing the feeding ratio of Mn-Pb ion and heat treatment temperature. Moreover, the introduction of Mn 2+ effectively improves the PLQY of CsPb(Br/Cl) 3 QDs glass and serves as a red-emitting. The prepared composites not only maintain good fluorescence characteristics, but also greatly improve the stability of quantum dots. Based on these advantages, the red-emitting perovskite quantum dot glass is expected to become a promising candidate for the high-power lighting material.
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