Central South University

Fan Zhao

Zuming Liu

Xueqian Lv

Quan Li

Kai Peng

Boyun Huang

Bing Wei

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.

Preparation method for iron-based alloy powder EBSD test sample

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.

Method for eliminating cracks in rené 104 nickel-based superalloy prepared by laser additive manufacturing

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&#x2014;Cr&#x2014;W&#x2014;Ti alloy. The strengthening phases include crystalline YOphase, Y&#x2014;Ti&#x2014;O phase, Y&#x2014;Cr&#x2014;O phase, and Y&#x2014;W&#x2014;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&#xb0; C.

Multi-scale and multi-phase dispersion strengthened iron-based alloy, and preparation and characterization methods thereof

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&#x2014;Cr&#x2014;W&#x2014;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.

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Hunan, China

Fan Zhao