Abstract: A method for preparing a nano-phase strengthened nickel-based superalloy using micron-scale ceramic particles is provided. In the method, a nickel-based superalloy is used as a matrix, and one or more of TiC, TiB2, WC and Al2O3 are used as a strengthening phase. A ceramic particle raw material used as the strengthening phase has a particle size of 1-5 ?m and is added in an amount of 1-5 wt. %. A nickel-based superalloy composite powder having homogeneously distributed nano-scale ceramic is prepared by mechanical milling. A nano-scale ceramic phase strengthened nickel-based superalloy is prepared by 3D printing technology, which has a homogeneously distributed nano-scale ceramic phase and excellent mechanical properties.

Abstract: A high-strength Al-Cu-Mg-Mn aluminum alloy and a preparation method therefor is provided. The alloy includes the following components in percentage by weight: Si:?0.5%, Fe: ?0.5%, Cu: 4.5-6.3%, Mg: 0.6-1.2%, Mn: 0.6-1.5%, Sc: 0.15-0.35%, Zr: 0.1-0.2%, and Y: 0.1-0.3%, the balance being aluminum and non-removable impurities. The preparation method includes: smelting, refining, impurity removing and degassing, pouring, homogenizing heat treatment, three-dimensional large deformation forging pre-deformation, isothermal deformation processing, and heat treatment. A casting mold used is a special combined mold having a metal mold as an inner mold, a surrounding cooling pipe, and a sand mold as an outer mold, and is used to prepare and obtain high-quality, high-performance castings. The heat treatment is solid solution treatment plus gradient aging treatment.

Abstract: The present disclosure relates to the field of additive manufacturing and superalloys, particularly to a method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing. For solving the problem that cracks are easily generated during laser additive manufacturing of René 104 nickel-based superalloy with high content of Al and Ti (Al+Ti>5 wt. %), generation of large-size cracks inside a fabricated part is suppressed by means of designing laser forming parameters and a partition scanning strategy; then stress relief annealing is performed to completely eliminate residual stress inside the fabricated part; and a spark plasma sintering process is performed to eliminate cracks inside the fabricated part and suppress the growth of grains during the sintering process.

Abstract: A characterization method of an oxide dispersion-strengthened (ODS) iron-based alloy powder is provided. The characterization method comprises separating the strengthening phases from the powder matrix through electrolysis, and analyzing and characterizing the strengthening phases using an electron microscope.

Abstract: A multi-scale and multi-phase dispersion strengthened iron-based alloy, and preparation and characterization methods thereof are provided. The alloy contains a matrix and a strengthening phase. The strengthening phase includes at least two types of the strengthening phase particles with different sizes. A volume of the two types of the strengthening phase particles with different sizes having a particle size less than or equal to 50 nm accounts for 85-95% of a total volume of all the strengthening phase particles. The matrix is a Fe—Cr—W—Ti alloy. The strengthening phases include crystalline Y2O3 phase, Y—Ti—O phase, Y—Cr—O phase, and Y—W—O phase. The characterization method comprises electrolytically separating the strengthening phases in the alloy, and then characterizing by using an electron microscope. The tensile strength of the prepared alloy is more than 1600 MPa at room temperature, and is more than 600 MPa at 700° C.

Abstract: An oxide dispersion-strengthened (ODS) iron-based alloy powder and a characterization method thereof are provided. The alloy powder comprises a matrix and strengthening phases. The strengthening phases include at least two types of strengthening phase particles with different sizes, wherein a volume of the particles with a particle size of less than or equal to 50 nm accounts for 85-95% of a total volume of all the strengthening phase particles. The matrix is a Fe—Cr—W—Ti alloy. The characterization method of the ODS iron-based alloy powder comprises separating the strengthening phases from the powder matrix through electrolysis, and analyzing and characterizing the strengthening phases using an electron microscope.

Abstract: A nickel-based superalloy for three-dimension (3D) printing and a powder preparation method thereof are provided. The method of preparing the nickel-based superalloy and its powder includes: RE microalloying combined with vacuum melting, degassing, refining, atomization with reasonable parameters, and a sieving process. The new method significantly reduces the cracking sensitivity of the “non-weldable” PM nickel-based superalloys, and broadens the 3D printing process window. The as-printed part has no cracks, and good mechanical properties. In addition, the powder prepared by the new method has higher sphericity and better flowability, and less irregular powders. The yield of fine powders with a particle size of 15-53 ?m and medium-sized powders with a particle size of 53-106 ?m that are required for 3D printing is greatly improved, which meet the requirements for 3D printing of high-quality, low-cost nickel-based superalloy powder.

Abstract: A preparation method for an iron-based alloy powder EBSD test sample includes the following steps: surface electrolytic activation of an iron-based powder; ultrasonically cleaning the powder, and drying the powder to obtain a surface activated powder; adding the surface activated powder to a chemical embedding solution for ultrasonic dispersion; after the ultrasonic dispersion, performing a plating process; then heating to 80-92° C. for chemical reaction to prepare an iron-based alloy bulk which coated with nickel. The plating process is as follows: still standing, stirring, and repeating the still standing is taken as a cycle, and at least one cycle is performed to complete the plating process. Then grinding and electropolishing are done to the obtained iron-based alloy bulk coated with nickel to obtain the iron-based alloy powder EBSD test sample.

Abstract: A multi-scale and multi-phase dispersion strengthened iron-based alloy, and preparation and characterization methods thereof are provided. The alloy contains a matrix and a strengthening phase. The strengthening phase includes at least two types of the strengthening phase particles with different sizes. A volume of the two types of the strengthening phase particles with different sizes having a particle size less than or equal to 50 nm accounts for 85-95% of a total volume of all the strengthening phase particles. The matrix is a Fe—Cr—W—Ti alloy. The strengthening phases include crystalline Y2O3 phase, Y—Ti—O phase, Y—Cr—O phase, and Y—W—O phase. The characterization method comprises electrolytically separating the strengthening phases in the alloy, and then characterizing by using an electron microscope. The tensile strength of the prepared alloy is more than 1600 MPa at room temperature, and is more than 600 MPa at 700° C.

Abstract: The present disclosure relates to the field of additive manufacturing and superalloys, particularly to a method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing. For solving the problem that cracks are easily generated during laser additive manufacturing of René 104 nickel-based superalloy with high content of Al and Ti (Al+Ti>5 wt. %), generation of large-size cracks inside a fabricated part is suppressed by means of designing laser forming parameters and a partition scanning strategy; then stress relief annealing is performed to completely eliminate residual stress inside the fabricated part; and a spark plasma sintering process is performed to eliminate cracks inside the fabricated part and suppress the growth of grains during the sintering process.

Abstract: An oxide dispersion-strengthened (ODS) iron-based alloy powder and a characterization method thereof are provided. The alloy powder comprises a matrix and strengthening phases. The strengthening phases include at least two types of strengthening phase particles with different sizes, wherein a volume of the particles with a particle size of less than or equal to 50 nm accounts for 85-95% of a total volume of all the strengthening phase particles. The matrix is a Fe—Cr—W—Ti alloy. The characterization method of the ODS iron-based alloy powder comprises separating the strengthening phases from the powder matrix through electrolysis, and analyzing and characterizing the strengthening phases using an electron microscope.