The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and diff...The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and differential scanning calorimeter （DSC） methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is （510 °C, 18 h）, which agrees well with the results of homogenization kinetic analysis.展开更多
Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at t...Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at temperatures between 200 and 600 ℃ for 60 min. The results show that the microstructure of tempered sample at 200 ℃ mainly consists of tempered martensite. With increasing the tempered temperature, the martensite transforms to the ferrite and carbides. The ultimate tensile strength, the hardness and the retained austenite decrease with increasing tempered temperature, and 0.2% yield strength increases when the temperature increases from 200 to 300 ℃ and then decreases with increasing the temperature, but the elongation and impact energy increase with increasing the tempering temperature.展开更多
文摘The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and differential scanning calorimeter （DSC） methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is （510 °C, 18 h）, which agrees well with the results of homogenization kinetic analysis.
基金Project(2011BAE13B03) supported by the National Key Technology R&D Program of China
文摘Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at temperatures between 200 and 600 ℃ for 60 min. The results show that the microstructure of tempered sample at 200 ℃ mainly consists of tempered martensite. With increasing the tempered temperature, the martensite transforms to the ferrite and carbides. The ultimate tensile strength, the hardness and the retained austenite decrease with increasing tempered temperature, and 0.2% yield strength increases when the temperature increases from 200 to 300 ℃ and then decreases with increasing the temperature, but the elongation and impact energy increase with increasing the tempering temperature.
