在半连续铸造过程中施加超声制备了ф1250 mm 2219铝合金大规格铸锭。利用光学显微镜、扫描电镜、电子万能试验机等仪器对常规铸锭和超声铸锭的微观组织与力学性能进行了检测与分析,探究超声作用的内在机制。结果表明：超声振动明显细...在半连续铸造过程中施加超声制备了ф1250 mm 2219铝合金大规格铸锭。利用光学显微镜、扫描电镜、电子万能试验机等仪器对常规铸锭和超声铸锭的微观组织与力学性能进行了检测与分析,探究超声作用的内在机制。结果表明：超声振动明显细化晶粒,减小截面上的晶粒尺寸不均匀性;改善组织形态,心部粗大的柱状晶转变为细小的球状等轴晶;有效抑制了晶内第二相的聚集和长大,使其呈均匀密集点状析出。超声不仅能有效提高铸锭各位置的综合力学性能,还能改善铸锭截面的力学均匀性。展开更多
A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observe...A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.展开更多
文摘在半连续铸造过程中施加超声制备了ф1250 mm 2219铝合金大规格铸锭。利用光学显微镜、扫描电镜、电子万能试验机等仪器对常规铸锭和超声铸锭的微观组织与力学性能进行了检测与分析,探究超声作用的内在机制。结果表明：超声振动明显细化晶粒,减小截面上的晶粒尺寸不均匀性;改善组织形态,心部粗大的柱状晶转变为细小的球状等轴晶;有效抑制了晶内第二相的聚集和长大,使其呈均匀密集点状析出。超声不仅能有效提高铸锭各位置的综合力学性能,还能改善铸锭截面的力学均匀性。
基金Funded by the National Natural Science Foundation of China(No.21476177)。
文摘A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.
