Papers by Keyword: Inclusion

Abstract: A preparation technology, characterization and release performance of pterostilbene cyclodextrin inclusion is investigated.

Abstract: The effect of RE on modifying inclusions of H13 die steel was studied by metallographic examination, SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in H13 die steel. The result shows that sulfide inclusions are modified to round RE complex inclusions after adding RE to H13 die steel.

Abstract: In this paper, the effective properties of magnetoelectroelastic heterogeneous materials with ellipsoidal multi-inclusions are modeled and numerically investigated. The modeling is based on the integral equation that takes into account the multi-coated effect as well as the magnetoelectroelastic interfacial operators and global and local concentration tensors. Various types and kinds of coatings can be considered. The effective properties are predicted based on various micromechanical models such as Mori-Tanaka, Self-Consistent and Incremental Self-Consistent. These properties are presented in terms of the volume fractions of the multi-coated inclusions, thicknesses of the coatings, type and kind of inclusions.

Abstract: The formation of alumina (Al₂O₃) inclusions was experimentally investigated with the capillary-reservoir method. The inclusions were observed with a SEM (scanning electron microscope). The compositions of iron matrix and inclusion were measured with an EDX (energy dispersive X-ray analysis). The content profile of aluminum was discussed by the counter-diffusion model of aluminum and oxygen with an instantaneous irreversible reaction for alumina formation. The inclusions of spherical and polygonal alumina and spherical hercynite (FeOAl₂O₃) were observed in the vicinity of the diffusion front of aluminum. The hercynite was detected when the initial oxygen content was 0.075 mass% and higher. When the initial oxygen content was more than 0.045 mass% and higher, dendritic alumina formed at the position that was nearer to the interface than the position of spherical and polygonal inclusions. No inclusion was observed around the interface because of the re-dissolution of the inclusions. The initiating position of the inclusion formation was approximated by the reaction position, Z_r, obtained from the model on the assumption that aluminum and oxygen contents at the reaction position were zero. Empirically, 0.9×Z_r and 0.17×Z_r expressed the initiating positions of formation and re-dissolution of inclusions respectively. The critical supersaturation ratio was estimated to be from 1 to 7.4×10⁵, depending on the initial aluminum and oxygen contents.

Abstract: The35kg ingot was refined with vacuum induction furnace by means of three various deoxidationprocesses in laboratory. From the steel-making point of view, effect of deoxidationprocess on inclusions and was analyzed. The fraction, size and distribution ofinclusions were studied with scanning electron microscope (SEM)and energy dispersive spectrometer (EDS) in three various deoxidation processessteel . The results showed that the volume fraction of inclusions was thelargest in Ti/Zr deoxidation process and the inclusions distributed uniformly. Itwas found that the amount of fine inclusions size in the range of 0.5~1.5 μmwas the largest atTi/Zr deoxidation process. The fraction of inclusions decreased with holdingtime increasing during alloying in present study.

Abstract: In order to improve fatigue life of wheel steel, secondary-refining process was done with Al-deoxidation and slag of high basicity, high Al2O3 content and low oxidizing property. By morphology observation and composition analysis with FESEM, it is found that during LF-VD process, by slag-steel-inclusion interaction, Al2O3 inclusions could transform to MgO-Al2O3 spinel, and later on to CaO-MgO-Al2O3 inclusions, which are inclined to be eliminated by floatation, lowering T[O] content to 0.0007%, enhancing fatigue life of wheel steel. By In-Situ observation with CONFOCAL laser scanning microscope, it is found that MnS precipitates during solidification process, which would core oxide inclusion to form MnS-oxide complex inclusion, contributing to fatigue life improvement of wheel steel. By INSTRON fatigue testing machine, it is found that by successful inclusion control, tested samples achieve ultra-high cycle of 108 above, realizing experimental purpose of improving fatigue life of wheel steel, boosting domestic production process of CRH high speed wheel steel.

Abstract: The aim of the present work was to determine the influence of air plasma spraying (APS) parameters on the microstructure of thermal barrier coatings (TBC) consisting on NiCoCrAlY bond coat and yttria - stabilized zirconia (YSZ) top coat. The scope of the investigation involved macroscopic observation and microstructural analysis by means of light microscopy (LM) and scanning electron microscopy (SEM). For the varied parameters of deposition process quantitative analysis of coatings thickness, porosity, oxide inclusions, metallic inclusions, globular inclusions and cracks were performed. The results of quantitative analysis allowed to establish which APS conditions influence the particular microstructural parameters of TBC coatings.

Abstract: According to the defects of powder metallurgy superalloy, especially the influence and damage of inclusions on properties of disk, the deviation between nondestructive testing and metallographic testing of inclusions in FGH96 alloy isothermal forging disk was investigated. Meanwhile, the types and deformation mechanism of inclusions were studied. The results showed that the buried depth tested by metallographic detection was less 67-180μm than nondestructive testing. The size of inclusions with metallographic detection was less about 18-50μm than nondestructive testing. The major types of inclusions in practical disk were Al₂O₃ and Al₂O₃-SiO₂, the inclusions run through several grains, no matter Al₂O₃ or Al₂O₃-SiO₂. The Al₂O₃ inclusion and matrix was purely mechanical bonding, but the Al₂O₃-SiO₂ had reaction zone. There was remarkable effect of extrusion process on crushing and dispersing Al₂O₃ inclusion, but which was unremarkable for Al₂O₃-SiO₂.

Abstract: Martensitic high carbon high strength SAE 52100 bearing steel is one of the main alloys used for rolling contact applications where high wear resistance are required. Due to its high fatigue strength, SAE 52100 is recently being used not only for the production of bearings but also shafts. In this work, quenched SAE 52100 steel fatigue strength under rotating bending was investigated. Especially, we focus on “fisheye around inclusion” where the fatigue crack starts. Quantitative evaluation of its optical micrograph has not been enough carried out. In order to develop easy evaluation method for the fisheye area, we apply homology technique to the optical observation.

Abstract: The effect of RE on modifying inclusions of 430 ferrite stainless steel was studied by metallographic examination, SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in 430 ferrite stainless steel. The result shows that sulfide and other irregular inclusions are modified to round or oval-shaped RE2O2S and RES.