The double directional solidification（DS） technique was developed to control the lamellar microstructures in primary β TiAl-Nb alloys.Polysynthetically twinned（PST） crystals with lamellar boundaries parallel to o...The double directional solidification（DS） technique was developed to control the lamellar microstructures in primary β TiAl-Nb alloys.Polysynthetically twinned（PST） crystals with lamellar boundaries parallel to or inclined 45o to the growth direction were achieved due to the complete peritectic transformation during directional solidification of the alloys with the dendritic solid/liquid interface.The PST crystals with aligned lamellar boundaries only parallel to the growth direction were produced when lamellar grains with lamellar boundaries in the same orientation were seeded by themselves under appropriate growth conditions.Low boron addition is harmful to align the lamellar orientation because of the growth of non-peritectic α phase.Due to the larger yttria particles and boride ribbons in the directionally solidified TiAl-Nb alloys,the tensile plastic elongations of the alloys are only close to 2%.展开更多
New solid complex of the antimony trichloride and dioxane was obtained th rough a reaction of the dioxane and the absolute methanol solution of the antimony trichloride.The formula of the complex is[SbCl_(3)·{(CH...New solid complex of the antimony trichloride and dioxane was obtained th rough a reaction of the dioxane and the absolute methanol solution of the antimony trichloride.The formula of the complex is[SbCl_(3)·{(CH_(2))_(4)O_(2)}_(1.5)].The crystal structure of the comple x belongs to cubic system,space group I-43d,a=17.1417(5)?,Z=16.The trivalent antimony ion not only bonds directly to three chlorine anions,but also is co ordinated by three oxygen atoms of th e dioxane molecules.Two oxygen atoms in a dioxane molecule wi ll coordinate to different antimony ions,respectively.展开更多
基金Project (2011CB605500) supported by the National Basic Research Program of ChinaProject (FRF-MP-10-005B) supported by the Fundamental Research Funds for the Central Universities,China
文摘The double directional solidification（DS） technique was developed to control the lamellar microstructures in primary β TiAl-Nb alloys.Polysynthetically twinned（PST） crystals with lamellar boundaries parallel to or inclined 45o to the growth direction were achieved due to the complete peritectic transformation during directional solidification of the alloys with the dendritic solid/liquid interface.The PST crystals with aligned lamellar boundaries only parallel to the growth direction were produced when lamellar grains with lamellar boundaries in the same orientation were seeded by themselves under appropriate growth conditions.Low boron addition is harmful to align the lamellar orientation because of the growth of non-peritectic α phase.Due to the larger yttria particles and boride ribbons in the directionally solidified TiAl-Nb alloys,the tensile plastic elongations of the alloys are only close to 2%.
文摘New solid complex of the antimony trichloride and dioxane was obtained th rough a reaction of the dioxane and the absolute methanol solution of the antimony trichloride.The formula of the complex is[SbCl_(3)·{(CH_(2))_(4)O_(2)}_(1.5)].The crystal structure of the comple x belongs to cubic system,space group I-43d,a=17.1417(5)?,Z=16.The trivalent antimony ion not only bonds directly to three chlorine anions,but also is co ordinated by three oxygen atoms of th e dioxane molecules.Two oxygen atoms in a dioxane molecule wi ll coordinate to different antimony ions,respectively.
