64 results about "Solidification microstructure" patented technology

The invention provides a prediction system and method for the thickness of an initially solidified shell in a continuous steel casting crystallizer. The system comprises an information collection module, a steel grade thermophysical parameter calculation module, a crystallizer initially solidified shell growth prediction module and a result output module. The method comprises the following steps: detecting a bleed-out shell microcosmic solidification structure; collecting initial information; computing the interdendritic solute segregation and solidification path in a molten steel solidification process to obtain a steel grade thermophysical parameter; solving a crystallizer molten steel flow field, a crystallizer temperature field and a crystallizer solute field, coupling a macroscopic transport process in the crystallizer and the evolution behavior of the microcosmic solidification structure in the crystallizer, and further predicting the shell growth behavior in the solidification process of high-temperature molten steel in the continuous steel casting crystallizer; outputting and displaying the comparative results of the predicted morphology of the solidification structure in the crystallizer, the predicted initially solidified shell thicknesses in different positions in the crystallizer and the actual thickness of the initially solidified shell. The system and the method can accurately predict the microcosmic solidification behavior of the initially solidified shell in the crystallizer.

The invention relates to H13 die steel and a preparation method thereof, and belongs to the technical field of wear-resistant materials. The H13 die steel comprises the following chemical elements in percentage by weight: 0.40 to 0.46 percent of C, 6.00 to 6.30 percent of Cr, 0.50 to 0.65 percent of V, 0.30 to 0.45 percent of Mo, 0.85 to 1.05 percent of Mn, 1.25 to 1.55 percent of Si, 0.12 to 0.25 percent of W, 0.008 to 0.018 percent of Nb, 0.008 to 0.015 percent of Ta, 0.08 to 0.12 percent of Ti, 0.003 to 0.006 percent of B, 0.08 to 0.15 percent of Al, 0.03 to 0.06 percent of N, 0.06 to 0.12percent of Y, less than 0.025 percent of S, less than 0.030 percent of P and the balance of Fe. The H13 die steel has the advantages that: the content of precious alloy elements, namely molybdenum and vanadium is low, the H13 die steel is not required to be forged, and forging can be replaced by casting, so that the cost of the H13 steel is obviously reduced; the performance of the H13 steel can be obviously improved, and a tungsten slag iron alloy is recycled; a solidification structure can be obviously refined, and the mechanical property of the H13 steel is improved; and the H13 steel has high wear resistance and is used as a hot working die, and the service life is prolonged.

The method of preparing Fe-Al-Ta multifunctional integrated material by Bridgman directional solidification technology changes the solidification structure characteristics by changing the solidification rate of different regions of the Fe-Al-Ta ternary alloy, thereby obtaining Fe-Al-Ta All-in-one material. At low solidification rate, the structure is lamellar eutectic. As the solidification rate increases, the structure transforms into rod-like eutectic. When the solidification rate increases further, the structure gradually transforms into spherical eutectic. Since solidification structures with different solidification rates have different properties, the properties of the material can be changed by changing the solidification rate in different regions, so that the properties of the material can be centralized, simplified and diversified, and a material with multiple functions can be prepared. The overall performance of the material is improved.

The invention discloses a high-hardness high-entropy alloy coating and its preparation method and application. The composition and atomic ratio of the high-entropy alloy coating are as follows: CoCrFeMnNiTi x V y , wherein x=0.3~1, y=0.1~1. The high-entropy alloy coating can be applied to high-temperature friction and wear materials, especially can be applied to milling cutter coating, high-temperature rotating shaft coating or high-temperature friction disc coating. The preparation method of the high-entropy alloy coating includes powder mixing, drying, pretreatment of base material and cladding coating. The plasma cladding CoCrFeMnNiTiV high-entropy alloy coating prepared by the invention is composed of a V-rich BCC1 phase and a Ti-rich BCC2 phase, and its solidification structure is a cellular dendrite structure. The average hardness of CoCrFeMnNiTiV high-entropy alloy coating reached 942.8HV 0.3 , 7.5 times that of the base Q235 steel.

The invention provides a high-alloy alloy casting rod casting crystallizer and a preparation method thereof. The casting crystallizer includes a water tank, a draft tube, a crystallizer and an electromagnetic coil assembly, and the draft tube is embedded in the water tank; the crystallizer is set In the chamber of the water tank, the upper end of the crystallizer is sealed and connected with the lower end of the draft tube, and the lower end of the crystallizer is sealed and connected with the side wall at the opening of the water tank; at least a first graphite ring is provided in the crystallizer, and the first graphite The rings are respectively connected to the water supply and gas supply systems, and a layer of vapor film is formed between the first graphite ring and the alloy casting rod; the electromagnetic coil assembly includes at least a plurality of L-shaped electromagnetic coils, and the plurality of electromagnetic coils They are all set close to the top of the crystallizer. By setting the first graphite ring and designing the electromagnetic coil into an L-shaped structure, the crystallizer can effectively improve the problems of coarse and uneven solidification structure and serious component segregation of high-alloy alloy cast rods, and at the same time improve the surface quality of the cast rods. Significant improvement.

The invention discloses a solidification preparation method of a Cu-Cr contact alloy, and belongs to the technical field of preparation of Cu-Cr contact alloy materials. TiB2 nucleating agent particles are added into the Cu-Cr alloy, when a fusant is cooled till liquid-liquid phase change occurs, the nucleating agent particles can serve as the nucleating substrate of Cr-rich phase liquid drops, thus the nucleating rate of the Cr-rich phase liquid drops is dramatically improved, and formation of a dispersion type Cu-Cr alloy composite solidification structure can be promoted. The solidificationpreparation method can be used for preparing high-quality Cu-Cr contact alloy materials.

The invention provides a method for improving the mechanical and magnetic properties of an AlCoCrCuFeNi high-entropy alloy through a magnetic field. The method includes the steps that Al, Co, Cr, Cu,Fe and Ni raw materials are smelted through a vacuum non-consumable electric arc smelting method, and an AlCoCrCuFeNi high-entropy alloy button ingot is obtained. An obtained high-entropy alloy buttonis placed in the magnetic field of 2-10 T for vacuum solidification, the yield strength sigma<y> of the obtained AlCoCrCuFeNi high-entropy alloy is 777-952 MPa, the tensile strength sigma is 1633-1903 MPa, the hardness is 374-413 HV, the saturation magnetization M<s> is 26.4-34.5 emu / g, and the shape of a solidification structure of the AlCoCrCuFeNi high-entropy alloy has no significant change. According to the method for improving the mechanical and magnetic properties of the AlCoCrCuFeNi high-entropy alloy through the magnetic field, the magnetic field is applied to the solidification process of the high-entropy alloy, and the purpose of simultaneously improving the mechanical and magnetic properties of the AlCoCrCuFeNi high-entropy alloy is achieved.

The present invention relates to a cast aluminum alloy used for high power density pistons and a preparation method thereof, wherein, a cast aluminum alloy is characterized in that: in terms of mass percentage, the cast aluminum alloy comprises the following components: Si: 11.0 ~12.6%, Cu: 3.5~4.5%, Mg: 0.7~1.2%, Ni: 2.2~3.2%, Fe: 0.6~0.8%, Mn: 0.25~0.35%, Sc: 0.10~0.15%, Zr: 0.13~ 0.17%, Ti: 0.13-0.17%, V: 0.08-0.12%, and the balance is Al and unavoidable impurities. Heat-resistant aluminum alloy is based on the thermodynamic analysis of the material system, microstructure control and experimental testing, by appropriately increasing and adjusting the relative addition of elements such as Fe, Ni, Cu, etc., to increase the 350‑420 °C high temperature support strengthening phase Al 9 FeNi, Al 15 Si 2 (Fe,Mn) 3 、Al 3 CuNi, Al 7 Cu 4 The content of Ni makes the solidification structure present scattered network, petal and diffuse stripe distribution. These high-temperature strengthening phases can hinder the grain boundary slip and dislocation movement in the alloy, and improve the heat resistance and grain boundary. Strength and creep resistance.

The invention relates to a method for fast preparing micron-level lamellar barium titanate powder. The prior art is complex in technology, long in preparation period, and low in production efficiency. The method sequentially comprises the following steps of: preparing KF-BaTiO3 or BaTiO3 melting body of a hypo eutectic component, and cooling and solidifying the melting body to obtain a solidified tissue; and ultrasonically cleaning the other phases in the solidified tissue to obtain sheet BaTiO3 crystalloid powder. The method specifically comprises the steps: (1) mixing BaCO3 power, TiO2 power with KF power, performing the ball milling by the polytetrafluoroethylene during mixing, performing the polytetrafluoroethylene to the agate, performing the ball milling and mixing for 6 hours with water-free ethanol medium, and drying for later use; (2) heating in a common crucible resistance furnace to be melted to obtain the melting body, and keeping the temperature for 1-4 hours for later use; (3) cooling the melting body to be solidified so as to obtain the solidified tissue; and ultrasonically cleaning to remove the KF and the other impurities in the solidified tissue.

The invention provides Mg-Zn-Cu-Zr-(Cr-Ca) alloy under the GPa level high pressure effect and a preparation method. A six-side ejecting hydraulic press is adopted to solidify the Mg-Zn-Cu-Zr-(Cr-Ca) alloy under the 2GPa-6GPa high pressure effect. The solidification structure characteristics, distribution of solute elements such as Zn, Cu and Ca, heterogeneous nuclei in high-pressure solidification, and strengthening and toughening mechanism are researched with the EBSD, SEM and other analytical methods. The results show that primary crystal alpha-Mg of the high pressure solidified alloy is regular isometric crystal. The average grain size is refined from 186[mu]m at the normal pressure to 22[mu]m at 6GPa. The solid solubility of Zn in the alpha-Mg matrix increases from 3.63% under the normal pressure to 6.23% under 6GPa. Intercrystalline second phase gradually changes from a network under the normal pressure to a discontinuous island or granular distribution under 6GPa. MgZn2, Mg2Ca and Cr2Zr phases are alpha-Mg crystal high-effective heterogeneous nuclear substrate in high-pressure solidification process. The number of crystal nucleus in the solidification process is greatly increased. The strength of the alloy increases with the increase of solidification pressure. Maximum resistance increases from 240MPa under atmospheric pressure to 520MPa under 6GPa during crushing.