Papers by Keyword: Oxide Inclusions

Abstract: Texture characteristics of compressed 1235 Al-alloy treated by different purification methods are studied by electron backscattered diffraction. The effects of oxide inclusions on texture components of material are studied as well. The main textures in hot-compressed 1235 Al-alloy are Cube texture, R texture, Gross texture, Brass texture, and Rotated cube texture. The lower the content of oxide inclusions in the material, the smaller the total relative ratio of textures. The total relative ratio of textures goes to the smallest by 1.8 % in high-efficient purified 1235 Al-alloy by oxide inclusion content of 0.051 %. The purification results have obvious effects on types and percentage of texture in the deformed alloy. With the decreasing content of oxide inclusion, the ratio of deformation texture decreases and recrystallization texture increases. Brass texture is gradually replaced by Goss texture in the deformation textures. R texture is the main texture in recrystallization textures. Therefore, reducing the content of oxide inclusions is effective for improving the hot deformation properties of 1235 Al-alloy.

Abstract: By welding thermo-simulation and actual welding practices, the microstructure and properties of low carbon bridge steels has been studied with the aid of optical microscope, scanning electron microscope. The experimental results show that by the oxide introducing melting technology there are many complex inclusions composed of oxide containing Ti and MnS. These inclusions are spherical and they are distributed homogeneously. During the welding thermo-simulation these oxide inclusions will promote the nucleation of acicular ferrite and make the microstructure in HAZ finer. Therefore the toughness in HAZ is good whether in welding thermo-simulation even if the heat input reaches to 200kJ/cm. In actual welding the heat input is 88kJ/cm and the low temperature impact energy still can reach 110J.

Abstract: The as-cast microstructure feature of Al sheet with high forming properties used for pressure can manufacturing pre-treated by different melt-treatment technique was observed and analyzed by SEM, EDAX, TEM and selected area electron diffraction (SAED), etc. It was found that the oxide inclusions in Al sheet were mainly γ-Al2O3, and the Fe-rich impurity phases in the sheet mainly Al3Fe, T1(Al12Fe3Si) or (AlFeSiRE). The crystal structure of (AlFeSiRE) phase was too complicated to be determined. The effect of melt-treatment technique on the as-cast microstructure of the sheet was remarkable. There were a number of oxide inclusions in the Al sheet before or after conventional melt-treatment, which distributed non-uniformly and gathered together in larger block shape with the size of about 10-40μm. The Fe-rich impurity phases in the sheet were mainly Al3Fe and T1, and a few of the meta-stable phase Al6Fe existed in the sheet. These Fe-rich impurity phases appeared in a coarse, long needle/flake or skeletal form, and were easily to gather together with oxide inclusions. When the Al sheet was treated by high-efficient melt-treatment, the amout of oxide inclusions was decreased obviously, and these inclusions distributed more uniformly in the tiny granular form (about or less than 4μm). The Fe-rich impurity phases were mainly (AlFeSiRE), and a small amount of Al3Fe phases also existed in the material. The (AlFeSiRE) phases distributed uniformly along grain boundary in tiny group/sphere or short stick form. No congregation of Fe-rich phases with oxide inclusions was found in the material.