Crystalline grain scale gradient metallic nickel and controllable preparation method thereof

Abstract

Aiming to the defect of a preparation method of a gradient metal material at present, the invention provides gradient metallic nickel being low in cost and easier in industrial production, and a preparation method of the gradient metallic nickel. The controllable preparation method is characterized in that an electroplating method is adopted to prepare the gradient metallic nickel, nickel is taken as a sacrificial anode, the variation of current density, additive concentration along with the time is controlled by a computer according to different microstructures or mechanical property requirements, nickel deposits under direct-current action to form crystalline grain scale gradient metallic nickel. The size of the gradient metallic nickel is almost not limited, the gradient distribution form is controllable, the size of a crystalline grain is gradually increased from 10-100 nm to 1-30 micron; no interfaces exist among hierarchical structure parts; the gradient metallic nickel is excellent in mechanical property, larger than or equal to 750 MPa in yield strength, 3-4 times of a traditional coarse grain in grain size, reaches more than 10% in tensile plastic deformation, and larger than or equal to 99.5% in overall sample density.

Description

technical field [0001] The invention relates to metallic nickel with grain size gradient and a controllable preparation method thereof with excellent mechanical properties. Background technique [0002] Gradient structure is a structural material that gradually transitions from one composition, organization or phase (or component) to another composition, organization or phase (or component), such as gradually transitioning from coarse grain to fine grain, or even amorphous structure. Different from traditional homogeneous simple materials or homogeneous single-level composite materials, gradient materials are characterized by heterogeneity and multi-scale organization, as well as multi-level structure. Due to the smooth organization and phase transition, the interface is widened or even disappeared. Different from traditional composite materials, this kind of structural gradient can not only effectively avoid the performance mutation caused by size mutation, but also make s...

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Problems solved by technology

[0004] Aiming at the lack of effective preparation methods for the current gradient structure metal materials, the present invention provides a gradient metal nickel with low cost and easier industrial production and a preparation method thereof. The size of this gradient structure metal nickel is almost unlimited (≥5mm, such as figure 1 ), the gradient distribution form is controllable, the grain size gradually increases from 10-100nm to 1-30μm, and there is no interface in each hierarchical structure (such as figure 2 shown); the gradient structure nickel metal has excellent mechanical properties, and its yield strength is ≥750MPa, which is 3-4 times that of the traditional coarse grain, and the tensile plastic deformation reaches more than 10%, and the overall sample density is ≥99.5%

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