阅读说明：本技术 一种共晶高熵合金的热机械处理方法 (Thermal mechanical treatment method of eutectic high-entropy alloy ) 是由 王志军 于 2019-10-25 设计创作，主要内容包括：本发明提供了一种共晶高熵合金的热机械处理方法,包括以下步骤：S1、多次轧制以及再结晶处理,S2、预应变以及时效处理；也就是将共晶合金进行多次轧制及再结晶处理,然后进行预应变和时效处理,得到热机械处理的共晶合金。本发明通过对共晶合金运用机械处理和多种热处理工艺,将界面强化、位错强化和析出强化结合起来,得到超高强共晶合金,具有广阔的工业应用前景。(The invention provides a thermomechanical treatment method of eutectic high-entropy alloy, which comprises the following steps: s1, rolling for multiple times and recrystallizing, S2, pre-straining and aging; namely, the eutectic alloy is rolled and recrystallized for a plurality of times, and then is pre-strained and aged to obtain the eutectic alloy with thermal mechanical treatment. The method combines interface strengthening, dislocation strengthening and precipitation strengthening by applying mechanical treatment and various heat treatment processes to the eutectic alloy to obtain the ultra-high-strength eutectic alloy, and has wide industrial application prospect.)

1. A thermal mechanical treatment method of eutectic high-entropy alloy is characterized by comprising the following steps:

s1, multiple rolling and recrystallization treatment

Rolling the eutectic high-entropy alloy to 68-77% of the original alloy thickness, annealing at 1150-1250 ℃ for 10-30 min, and repeating the rolling and annealing operations once to obtain the dual-phase high-entropy alloy with the total deformation of 42-52%;

s2, prestrain and aging treatment

And (3) carrying out 10-40% pre-strain on the rolled eutectic high-entropy alloy obtained from S1, then carrying out aging treatment at 600-750 ℃, preserving heat for 1-12 h, and carrying out water quenching to obtain the thermo-mechanically treated eutectic high-entropy alloy.

2. The method of claim 1, wherein the eutectic high entropy alloy is a eutectic high entropy alloy comprising both soft and hard phases.

3. Method for the thermomechanical treatment of a eutectic high entropy alloy, according to claim 2, wherein the eutectic high entropy alloy is Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂Or Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂。

Technical Field

The invention relates to the technical field of materials, in particular to a thermal mechanical treatment method of eutectic high-entropy alloy.

Background

High-entropy alloy (HEA) is an alloy obtained by mixing five or more elements in equal proportion or approximately equal proportion. High-entropy alloys have received much attention in recent years because of their excellent physicochemical properties under a variety of conditions. The traditional alloy is mainly composed of an element as a base element, such as iron, and some trace elements are added to improve the performance of the traditional alloy. The traditional theory considers that the mixture of various elements forms intermetallic compounds, so that the material is embrittled, and the high-entropy alloy breaks through the theoretical understanding and generally shows good plasticity. Among them, the eutectic high-entropy alloy is a typical high-entropy alloy with excellent strong plastic bonding.

The thermal mechanical treatment is an effective means for further improving the mechanical property of the eutectic high-entropy alloy. By adjusting the thermo-mechanical treatment process, multiple microstructure forms such as two-phase complete recrystallization, incomplete recrystallization and recrystallization can be obtained while keeping the structure of a eutectic chip, and the like, so that the mechanical property of the eutectic chip is remarkably improved. However, at present, a thermomechanical processing technology of the eutectic high-entropy alloy is still lack of systematic and deep research, and precipitation strengthening and dislocation strengthening cannot be introduced into the thermomechanical processing technology, so that the mechanical property of the high-entropy alloy still has a large promotion space.

Disclosure of Invention

The invention aims to provide a thermal mechanical treatment method of eutectic high-entropy alloy, which combines interface strengthening, dislocation strengthening and precipitation strengthening by reasonably designing and applying rolling and thermal treatment processes in the eutectic high-entropy alloy, and remarkably improves the mechanical property of as-cast high-entropy alloy. Wherein the interface strengthening is the inherent strengthening mode of the eutectic alloy; dislocation strengthening and precipitation strengthening can be obtained by reasonably designing pre-strain rolling and aging heat treatment.

In order to achieve the purpose, the invention adopts the technical scheme that:

the thermomechanical treatment method of the eutectic high-entropy alloy comprises the following steps:

s1, multiple rolling and recrystallization treatment

Rolling the eutectic high-entropy alloy to 68-77% of the original alloy thickness, annealing at 1150-1250 ℃ for 10-30 min, and repeating the rolling and annealing operations once to obtain the eutectic high-entropy alloy with the total deformation of 42-52%;

s2, prestrain and aging treatment

And (3) carrying out 10-40% pre-strain on the rolled eutectic high-entropy alloy obtained from S1, then carrying out aging treatment at 600-750 ℃, preserving heat for 1-12 h, and carrying out water quenching to obtain the thermo-mechanically treated eutectic high-entropy alloy.

Preferably, the eutectic high entropy alloy to which the thermomechanical treatment method is applied is a two-phase high entropy alloy comprising both soft and hard phases.

Preferably, the eutectic high-entropy alloy is Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂Or Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂。

Compared with the prior art, the invention has the following beneficial effects:

1. according to the invention, through multiple rolling and recrystallization treatments, the strain energy accumulated by single rolling is not enough to initiate the recrystallization behavior of the recrystallized alloy, and the strength and the plasticity of the alloy are improved; the rolling and heat treatment process is reasonably designed and applied, the interface strengthening, the dislocation strengthening and the precipitation strengthening are combined, the mechanical property of the as-cast high-entropy alloy is obviously improved, the precipitation phase formation is promoted by utilizing the methods of pre-strain and direct aging, and the ultrahigh-strength eutectic high-entropy alloy is obtained;

2. the invention also relates to Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂The thermomechanical treatment process of the eutectic high-entropy alloy is researched, and the optimal thermomechanical treatment process is obtained by the following steps: alloy ingot casting → rolling for 70% of original thickness → 1200 ℃ recrystallization for 20min, under the process, the elongation after breakage is increased from 5% to 25.2%, and the strength is also greatly improved; the invention also relates to Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂The thermomechanical treatment process of the eutectic high-entropy alloy is researched, and the optimal thermomechanical treatment process is obtained by the following steps: alloy ingot → rolling to 75% of original thickness → 1200 ℃ recrystallization 20 min;

3. co of the invention₃₀Ni₃₀Fe₁₀Cr₁₀Al₁₈W₂After 30% pre-strain treatment, the optimal aging temperature and time of the eutectic high-entropy alloy are 700 ℃ and 3h respectively, the alloy hardness is 488.18HV, the yield strength is 1081.6MPa, the tensile strength is 1711.9MPa, and the elongation after fracture reaches 14.9%. Under the same heat treatment process, the tensile strength is improved by 40 percent when the pre-strain is increasedThe degree reaches 1782.1 MPa; thermo-mechanically treated Ni in the present invention₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂Lamellar tissues are partially reserved in the eutectic high-entropy alloy, a large number of strip-shaped nanometer phases rich in Co and Cr and granular nanometer phases rich in W are separated out in the hard-phase face-centered cubic structure, ordered nanometer particles are separated out in the soft-phase face-centered cubic structure, and the separated phases greatly improve the strength of the alloy and reduce the molding reduction.

Drawings

FIG. 1 shows that the eutectic high-entropy alloy Ni is obtained in the embodiments 1 to 5 by aging at 700 ℃ for different times₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂A hardness map of (a);

FIG. 2 shows the eutectic high-entropy alloys Ni of examples 1 to 5 aged at 700 ℃ for different times₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂Stress strain curve of (a);

FIG. 3 shows that the eutectic high-entropy alloy Ni is obtained from the alloys in different aging temperatures and different aging times, namely, in examples 1 to 20 and comparative example 1₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂A hardness map of (a);

FIG. 4 shows the eutectic high entropy alloys Ni obtained in examples 10, 9, 1, 18 and 1 by optimum time treatment of alloys at different aging temperatures₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂Stress strain curve of (a);

FIG. 5 shows the eutectic high entropy alloy Ni obtained by different pre-strain treatments of the alloy in examples 1, 21 to 23 and comparative example 1₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂Stress strain curve of (a);

FIG. 6 is Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈W₂The eutectic high-entropy alloy being as-cast, the alloy being rolled only, the alloy being rolled and recrystallised and the alloy being subjected to a complete thermomechanical treatment, i.e.Gold phase diagrams for the samples of comparative example 2, comparative example 3, comparative example 1, and example 1;

in the figure: (a) (b) is the sample of comparative example 2, (c) (d) is the sample of comparative example 3, (e) (f) is the sample of comparative example 1, (g) (h) is the sample of example 1;

FIG. 7 is a transmission plot and an electron diffraction pattern of the FCC structure for the sample of example 1;

in the figure: (a) transmission electron microscopy images of the FCC structure, (b) high-resolution electron microscopy images of FCC, and (c) electron diffraction patterns of the [011] crystallographic band axis of the FCC phase;

FIG. 8 is a transmission plot and an electron diffraction pattern of the B2 structure of the sample of example 1;

in the figure: (a) (B) a transmission electron microscope photograph showing a structure of B2, and (c) an electron diffraction pattern of a [001] band axis of a B2 phase;

FIG. 9 is a plot of the compositional sweep results for phase B2 for the sample of example 1;

FIG. 10 is a transmission picture after tensile failure of the sample of example 1;

in the figure: (a) FCC structure for the alloy after fracture, (B) B2 structure for the alloy after fracture;

FIG. 11 shows Ni obtained in comparative example 4₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂Scanning a scanning image of an as-cast sample of the eutectic high-entropy alloy;

FIG. 12 is a thermo-mechanically treated Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂、Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂As-cast and Ni₃₀Co₃₀Fe₁₀Cr₁₀Al₁₈Nb₂The stress-strain profiles of the samples of example 24, comparative example 4 and comparative example 5 were rolled and recrystallized.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments. The scope of the invention is not limited to the specific embodiments.