A Ni-based bulk amorphous alloy with high plasticity at room temperature and a preparation method thereof

Abstract

The present invention relates to a Ni-based bulk amorphous alloy with high plasticity at room temperature and a preparation method thereof. 76‑ x Co x Nb 4 P 16 B 4 (x=5, 10, 15 and 20 at.%), wherein x represents the atomic percentage of the Co element in the alloy. The present invention adopts Fluxing and J-quenching technology to prepare an amorphous alloy rod. When x=5 at.%, it has a room temperature compression plasticity of 27%, a yield strength of 2596 MPa, and a fracture strength of 3559 MPa. The Ni-based bulk amorphous alloy of the present invention has excellent plastic deformation ability and can also achieve higher strength through work hardening. Therefore, the Ni-based bulk amorphous alloy has potential value in the application field as a structural material.

Description

Technical Field

[0001] The present invention relates to the field of amorphous alloy materials, and in particular to a Ni-based bulk amorphous alloy with high plasticity at room temperature and a preparation method thereof. The Ni-based bulk amorphous alloy has excellent compression plasticity and good work hardening ability at room temperature. Background Art

[0002] Bulk amorphous alloys have attracted extensive attention from researchers in the past few decades due to their excellent mechanical properties such as high strength and high elastic strain limit. As candidates for structural materials, bulk amorphous alloys have poor plasticity while performing better than crystalline materials, which will seriously limit their wide application in the engineering field. Therefore, the development of bulk amorphous alloys with high plasticity at room temperature is of great value and significance to prevent their brittle fracture without warning in engineering applications as structural materials. Summary of the invention

[0003] The purpose of the present invention is to provide a Ni-based bulk amorphous alloy with high plasticity at room temperature. The Ni-based bulk amorphous alloy provided by the present invention effectively solves the problem of insufficient deformation ability of amorphous alloys at room temperature.

[0004] Another object of the present invention is to provide a method for preparing the above-mentioned Ni-based bulk amorphous alloy.

[0005] The specific steps of the method for preparing the Ni-based bulk amorphous material with large plastic deformation at room temperature are as follows.

[0006] (1) Preparation of master alloy ingot: Weigh the percentage of each atom in the above-mentioned Ni-based bulk amorphous alloy structure and load it into a quartz tube. Then connect the quartz tube to a vacuum system and evacuate it. When the vacuum degree reaches about 50 Pa, introduce Ar gas for purging. The above purging operation is repeated 4 times. Finally, use a torch to melt the raw materials in the quartz tube into an alloy ingot.

[0007] (2) The alloy ingot melted in step (1) is placed in a molten purification medium consisting of B2O3 and CaO in a mass ratio of 3:1, and purified in a furnace at a temperature of 1150°C for 3 hours.

[0008] (3) The alloy ingot purified in step (2) is placed in a quartz tube prepared in advance and subjected to vacuum treatment. When the vacuum degree reaches about 50 Pa, Ar gas is introduced for gas washing. The above gas washing operation is repeated 4 times. After the gas washing is completed, the purified alloy ingot is burned to a molten state with a torch, and quickly inserted into a vertical sintering furnace. The vacuum control valve is opened to vacuumize for 30 seconds, and then Ar gas is introduced to push the molten alloy ingot into the bottom of the quartz tube, keep it warm for a certain period of time, and finally take it out and quickly quench it in water.

[0009] The Ni-based bulk amorphous alloy provided by the present invention has the advantages of having very excellent room temperature plastic deformation ability and being able to improve its strength through work hardening, with a room temperature compression plastic deformation of about 7% to 27%, a compression yield strength of 2146 MPa to 2596 MPa, and a fracture strength of 2188 MPa to 3559 MPa. The present invention provides a new Ni-based bulk amorphous alloy material with high room temperature plasticity, which has broad application prospects in the field of structural materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 3 is the XRD diagram of the Ni-based bulk amorphous alloy in Examples 1-4 of the present invention.

[0011] Figure 2 It is the room temperature compressive stress-strain curve of the Ni-based bulk amorphous alloy in Examples 1-4 of the present invention.

[0012] Figure 3 It is a scanning electron microscope image of the cylindrical shear band of the Ni-based bulk amorphous alloy corresponding to Example 1 of the present invention. Implementation

[0013] The present invention provides a Ni-based bulk amorphous alloy with high plasticity at room temperature, the structural formula of which is Ni 76- x Co x Nb4P 16 B4 (x=5, 10, 15 and 20 at.%), x is the atomic percentage of Co in the alloy, and its specific preparation steps are as follows.

[0014] Preparation of bulk amorphous alloys of Examples 1-4 (x=5, 10, 15 and 20 at.%).

[0015] Step 1: According to the corresponding Ni in each embodiment 76-x Co x Nb4P 16The atomic mass fraction percentage of each element in the B4 (x = 5, 10, 15 and 20 at.%) bulk amorphous alloy is used to calculate the required nickel powder (99.8%), cobalt powder (99.8%), cobalt phosphide (98%), niobium powder (99.8%), and boron powder (99.9%) content. The weighed components are placed in a quartz tube and connected to a vacuum system for vacuuming. When the vacuum reaches about 50 Pa, Ar gas is introduced for gas washing, and the gas washing is repeated 4 times. Finally, the components in the quartz tube are melted into alloy ingots with a torch.

[0016] Step 2: Place the melted alloy ingot into a molten purification medium consisting of B2O3 and CaO in a mass ratio of 3:1, and perform purification treatment in a furnace at a temperature of 1150°C for 3 hours.

[0017] Step 3: Place the alloy ingot purified in step 2 in alcohol for ultrasonic cleaning for about 30 seconds, then take it out and dry it and put it into the quartz tube prepared in advance. Connect the quartz tube to a mechanical pump for vacuuming. When the vacuum degree reaches about 50 Pa, introduce Ar gas for gas washing. Repeat the gas washing operation 4 times, then use a torch to burn the alloy ingot to a molten state, quickly insert it into a vertical sintering furnace, immediately open the vacuum control valve to vacuum for 30 seconds, and finally introduce Ar gas to push the alloy ingot into the bottom of the quartz tube. After keeping warm for about 45 seconds, take out the quartz tube and quickly quench it in water.

[0018] Determination of properties of Examples 1-4.

[0019] The structures of Examples 1-4 were characterized by X-ray diffraction. Figure 1 As shown, each critical size of Examples 1-4 has only one obvious diffuse peak, which is a typical structural feature of an amorphous alloy, and no corresponding sharp crystal phase peak appears, which can be determined to be an amorphous structure.

[0020] The room temperature compressive mechanical properties of Examples 1-4 with a diameter of 1 mm, a length of 2 mm, and a height-to-diameter ratio of 2:1 were measured using a universal mechanical testing machine. The compressive strain rate was 4×10 -4 s -1 The stress-strain curve is as follows Figure 2 shown.

[0021] Scanning electron microscopy (SEM) was used to observe the morphology of the cylindrical shear band of Example 1 after compression with a diameter of 1 mm, a length of 2 mm, and an aspect ratio of 2:1. Figure 3 shown.

[0022] Comparative analysis of mechanical properties of Examples 1-4.

[0023] The plastic strains of Examples 1-4 are 27%, 19%, 16%, and 7%, respectively, and show a decreasing trend with the increase of Co content. The yield strength and fracture strength of Examples 1-3 gradually decrease with the increase of Co content, and the corresponding yield strength and fracture strength increase slightly in Example 4. Figure 3 Scanning electron microscopy can be observed that the fracture side area of ​​Example 1 presents dense primary and secondary shear bands, that is, better compression plasticity. The compression stress-strain curves of Examples 1-4 all have obvious work hardening phenomenon, resulting in increased strength of each example.

Claims

1. A Ni-based bulk amorphous alloy with high plasticity at room temperature, characterized in that: Its composition is Ni 71 Co5Nb4P 16 B4, the method for preparing the Ni-based bulk amorphous alloy with high plasticity at room temperature comprises the following steps: (1) Ni 71 Co5Nb4P 16 B4 bulk amorphous alloy, the raw materials used to prepare the alloy have the following purities: nickel powder (99.8%), cobalt powder (99.8%), cobalt phosphide (98%), niobium powder (99.8%), and boron powder (99.9%); (2) weighing the raw materials of the required mass of each component according to the proportion of each atom in the chemical formula of the alloy, and placing them into a quartz tube; (3) evacuating the raw materials weighed in the quartz tube in step (2) and washing them with Ar gas, repeating the washing operation four times, and then using a torch to melt the raw materials in the quartz tube into an alloy ingot; (4) placing the alloy ingot melted in step (3) into a molten purification medium composed of B2O3 and CaO in a mass ratio of 3:1 for purification, wherein the temperature is controlled at 1150°C and the purification is carried out for 3 hours; to prevent the alloy ingot from being oxidized, vacuum is evacuated throughout the purification process; every 10 minutes for one hour before the purification, the quartz tube containing the alloy ingot is taken out of the purification furnace to observe whether there is any re-calendering phenomenon, and the above operation is repeated every 30 minutes for the next two hours; (5) The alloy ingot purified in step (4) is placed in a prefabricated quartz tube, and subjected to vacuuming and Ar gas washing treatment for four times. The alloy ingot in the quartz tube is burned to a molten state with a torch, and then quickly inserted into a vertical sintering furnace. The vacuum control valve is opened to vacuumize for 30 seconds, and then Ar gas is introduced to push the molten alloy ingot into the bottom of the quartz tube, keep it warm for a certain period of time, and finally quickly quench it into water.

2. The Ni-based bulk amorphous alloy with high room temperature plasticity according to claim 1, characterized in that When the vacuum is drawn in steps (3) and (5), the vacuum degree is 50 Pa.

3. The Ni-based bulk amorphous alloy with high room temperature plasticity according to claim 1 or 2, characterized in that The quartz tube used in step (5) consists of two parts: a thin tube and a thick tube, and the thin tube corresponds to the bottom of the quartz tube.

4. The Ni-based bulk amorphous alloy with high room temperature plasticity according to claim 3, characterized in that In the step (5), the temperature of the vertical sintering furnace is set to 1290° C., and the holding time is 45 seconds.

Images