A new model to study the hydriding/dehydriding （H/D） kinetic mechanism has been applied in the two-phase （α-β） region of the Mg-6mol%LaNi composite at temperature and pressure ranging from 523 to 623K and 0.256 ...A new model to study the hydriding/dehydriding （H/D） kinetic mechanism has been applied in the two-phase （α-β） region of the Mg-6mol%LaNi composite at temperature and pressure ranging from 523 to 623K and 0.256 to 0.992MPa H2. respectively. The coincidence of the theoretical calculation with the experimental data indicates that the rate-limiting step is hydrogen diffusion in the β phase for hydriding process and the diffusion of hydrogen in the α solid solution for hydrogen desorption with activation energies 89500 and 87900J/mol H2 for HID processes, respectively, which were much smaller than those of MgH2 and can be attributed to the La and Ni additions.展开更多
A novel two-step cooling experiment was established to simulate the slow cooling process of continuous annealing production line for transformation-induced plasticity （TRIP） steel. The microstructures and mechanical...A novel two-step cooling experiment was established to simulate the slow cooling process of continuous annealing production line for transformation-induced plasticity （TRIP） steel. The microstructures and mechanical properties of TRIP steel soaked at 700℃ for different time were investigated by tensile test, scanning electron microscopy, X-ray diffraction, and thermodynamic and kinetic calculation. It is shown that the steel soaked for 15 s exhibits the optimal product of strength and elongation （PSE 〉 30,000 MPa%） due to the transformation of austenite to proeutectoid ferrite, which delays the bainite transformation and improves the stability of retained austenite. In addition, the mechanical properties of TRIP steel soaked over 30 s are much lower, resulting from the precipitation of cementite, which decreases the stability of retained austenite and weakens the TRIP effect.展开更多
基金the Science and Technology Committee of Shanghai （No. 0452NM002） Postdoctoral Science Foundation of China （No. 2004036009）+1 种基金 the National Natural Science Foundation of China （No. 50274008）Shanghai Postdoctoral Science Foundation （No. 04R214120）.
文摘A new model to study the hydriding/dehydriding （H/D） kinetic mechanism has been applied in the two-phase （α-β） region of the Mg-6mol%LaNi composite at temperature and pressure ranging from 523 to 623K and 0.256 to 0.992MPa H2. respectively. The coincidence of the theoretical calculation with the experimental data indicates that the rate-limiting step is hydrogen diffusion in the β phase for hydriding process and the diffusion of hydrogen in the α solid solution for hydrogen desorption with activation energies 89500 and 87900J/mol H2 for HID processes, respectively, which were much smaller than those of MgH2 and can be attributed to the La and Ni additions.
基金This work was supported by National Key R＆D Program of China （Grant No. 2017YFB0304402） and the Shanghai Municipal Natural Science Foundation （Grant No. 17ZR1410400）.
文摘A novel two-step cooling experiment was established to simulate the slow cooling process of continuous annealing production line for transformation-induced plasticity （TRIP） steel. The microstructures and mechanical properties of TRIP steel soaked at 700℃ for different time were investigated by tensile test, scanning electron microscopy, X-ray diffraction, and thermodynamic and kinetic calculation. It is shown that the steel soaked for 15 s exhibits the optimal product of strength and elongation （PSE 〉 30,000 MPa%） due to the transformation of austenite to proeutectoid ferrite, which delays the bainite transformation and improves the stability of retained austenite. In addition, the mechanical properties of TRIP steel soaked over 30 s are much lower, resulting from the precipitation of cementite, which decreases the stability of retained austenite and weakens the TRIP effect.
