CN102978541B - Shape-memory crystalline-phase strengthened and toughened Ti-base amorphous composite material and preparation method thereof - Google Patents

Abstract

A Ti-based amorphous composite material strengthened and toughened by a shape-memory crystalline phase and a preparation method thereof. The composition of the composite material is (Ti _0.50 Ni _0.50-y M _y ) _{100-x Cux} , wherein: M is Fe, One or several elements of Co, Nb, Al, Zr, Si, x=5~33, y=0~0.25, this composition has a certain shape memory effect and high amorphous forming ability, and is precipitated in situ from the amorphous matrix The plastic phase-supercooled austenite phase is toughened, and the supercooled austenite in the shape memory alloy undergoes thermoelastic martensitic phase transformation under deformation induction to make the amorphous work hardening to strengthen the matrix. The composite material It exhibits excellent comprehensive mechanical properties, the compressive yield strength is 1000~1800MPa, the fracture strength is 1400~2800MPa, the plastic deformation is 10%~20%, and it shows strong work hardening.

Description

Shape memory crystalline phase toughened Ti-based amorphous composite material and preparation method thereof

technical field

The invention relates to the field of Ti-based amorphous composite materials, in particular to a composition of a shape-memory crystal phase reinforced and toughened Ti-based amorphous composite material and a preparation method thereof.

Background technique

Titanium-based amorphous has the advantages of low density, high strength, good wear resistance and corrosion resistance, and biocompatibility, and has great application prospects in aerospace, machinery, construction, energy, and biomedicine. However, due to the long-range disordered and short-range ordered structure of the atomic arrangement of amorphous alloys, the lack of work hardening mechanisms such as dislocations and slips of conventional crystalline metal materials during deformation, the highly localized shear behavior makes its plasticity and fracture at room temperature Low toughness limits the wide application of amorphous alloys as structural materials in engineering. In recent years, people have proposed a variety of methods for toughening amorphous alloys. The introduction of the second phase can be selected according to various performance indicators. The structure and properties of BMG-based composites can be designed, and it is an effective BMG toughening method. method.

For example, in 2008, W. L. Johnson’s research group developed a β-phase dendrite-toughened composite material with significant plasticity in the titanium-based amorphous alloy system by adjusting the alloy composition and semi-solid treatment. The total tensile deformation at room temperature The ratios are 10.8% and 13.1%, respectively, and the reduction of area is 50% and 46%. The plasticity and toughness index of this material has reached the index range of traditional metal materials, but it still shows strain softening after deformation and yielding, which makes engineering popularization. certain restrictions.

Contents of the invention

The object of the present invention is to provide a Ti-based amorphous composite material strengthened and toughened by a shape memory crystal phase and a preparation method thereof.

The invention relates to a Ti-based amorphous composite material strengthened and toughened by a shape-memory crystalline phase and a preparation method thereof, a Ti-based amorphous composite material strengthened and toughened by a shape-memory crystalline phase, a Ti-based amorphous alloy and a supercooled material capable of producing deformation-induced phase transitions It is composed of austenite phase B2-TiNi and martensite phase B19'-TiNi.

The preparation method of the Ti-based amorphous composite material strengthened and toughened by the shape memory crystal phase comprises the following steps:

(1) Ingredients:

Each component is weighed by (Ti _0.50 Ni _0.50-y M _y ) _100-x Cu _x nominal composition shown in claim 1;

(2) Melting (Ti _0.50 Ni _0.50-y M _y ) _100-x Cu _x master alloy:

Put the required raw materials weighed in step (1) into the vacuum high-frequency electromagnetic induction heating furnace;

Adjust the vacuum degree of the vacuum magnetic levitation melting furnace to 2×10 ^-3 ~ 5×10 ^-3 Pa, and then fill the high-purity argon to make the vacuum degree of the vacuum chamber to 0.1×10 ^-3 ~ 0.8×10 ^-3 Pa to melt the alloy ingot repeated smelting at least three times;

(3) Preparation of amorphous composite material samples by copper mold suction casting method:

Put the (Ti _0.50 Ni _0.50-y M _y ) _100-x Cu _x master alloy prepared in step (2) into a suspension melting water-cooled crucible for remelting, and adjust the vacuum degree of the vacuum magnetic levitation melting furnace to 2×10 ^-3 ~5× 10 ^-3 Pa, and then filled with high-purity argon to make the vacuum of the vacuum chamber to 0.1×10 ^-3 ~0.8×10 ^-3 Pa;

After smelting for 1-3 minutes under the induction voltage of 5-10kV, the master alloy is suction-cast into rods by negative-pressure copper mold suction casting.

Compared with the prior art, the present invention has significant advantages: the invented composite material uses Ti-based amorphous alloy as matrix material, compared with single-phase amorphous alloy and previous endogenous Ti-based amorphous composite material, the matrix has The shape memory crystalline phase with deformation-induced phase transition properties is precipitated as a strong and tough phase, achieving the purpose of significantly improving strength and plasticity, and exhibiting strong work hardening.

Description of drawings

Figure 1 is the as-cast XRD pattern of a Ti-based amorphous composite material with a diameter of 3 mm, Figure 2 is the XRD pattern of a Ti-based amorphous composite material with a diameter of 3 mm after stress loading and fracture, and Figure 3 is the XRD pattern of a Ti-based amorphous composite material with a diameter of 3 mm Compressive stress-strain curves at room temperature.

Detailed ways

The invention relates to a Ti-based amorphous composite material strengthened and toughened by a shape-memory crystalline phase and a preparation method thereof, a Ti-based amorphous composite material strengthened and toughened by a shape-memory crystalline phase, a Ti-based amorphous alloy and a supercooled material capable of producing deformation-induced phase transitions It is composed of austenite phase B2-TiNi and martensite phase B19'-TiNi.

The preparation method of the Ti-based amorphous composite material strengthened and toughened by the shape memory crystal phase comprises the following steps:

(1) Ingredients:

Each component is weighed by (Ti _0.50 Ni _0.50-y M _y ) _100-x Cu _x nominal composition shown in claim 1;

(2) Melting (Ti _0.50 Ni _0.50-y M _y ) _100-x Cu _x master alloy:

Put the required raw materials weighed in step (1) into the vacuum high-frequency electromagnetic induction heating furnace;

Adjust the vacuum degree of the vacuum magnetic levitation melting furnace to 2×10 ^-3 ~ 5×10 ^-3 Pa, and then fill the high-purity argon to make the vacuum degree of the vacuum chamber to 0.1×10 ^-3 ~ 0.8×10 ^-3 Pa to melt the alloy ingot repeated smelting at least three times;

(3) Preparation of amorphous composite material samples by copper mold suction casting method:

Put the (Ti _0.50 Ni _0.50-y M _y ) _100-x Cu _x master alloy prepared in step (2) into a suspension melting water-cooled crucible for remelting, and adjust the vacuum degree of the vacuum magnetic levitation melting furnace to 2×10 ^-3 ~5× 10 ^-3 Pa, and then filled with high-purity argon to make the vacuum of the vacuum chamber to 0.1×10 ^-3 ~0.8×10 ^-3 Pa;

After smelting for 1-3 minutes under the induction voltage of 5-10kV, the master alloy is suction-cast into rods by negative-pressure copper mold suction casting.

The present invention is described in detail below through specific examples.

Example 1:

The composition of the Ti-based amorphous composite material is (Ti _0.5 Ni _0.5 ) ₈₀ Cu ₂₀ , select Ti and Cu with a purity greater than 99.99%, and Zr and Al with a purity of 99.9%. In the high-frequency electromagnetic induction heating furnace, adjust the vacuum degree of the vacuum magnetic levitation melting furnace to 2×10 ^-3 ~5×10 ^-3 Pa, and then fill the high-purity argon to make the vacuum degree of the vacuum chamber to 0.1×10 ^-3 ~0.8× Melting at 10 ^-3 Pa, the alloy ingot was smelted repeatedly at least three times. Then put the master alloy into the suspension smelting water-cooled crucible for remelting, adjust the vacuum degree of the vacuum magnetic levitation melting furnace to 2×10 ^-3 ~ 5×10 ^-3 Pa, and then fill the high-purity argon to make the vacuum degree of the vacuum chamber to 0.1× 10 ^-3 ~ 0.8×10 ^-3 Pa. After melting for 1-3 minutes at an induced voltage of 5-10 kV, the master alloy is suction-cast into a rod with a diameter of 3 mm by a negative-pressure copper mold suction casting method.

Figure 1 is the as-cast XRD pattern of the suction casting sample. In addition to the typical amorphous diffuse scattering peaks, there are sharp crystal diffraction peaks superimposed on the diffuse scattering peaks, indicating that the sample is a composite structure of amorphous and crystalline. The main crystal phase precipitated is B2-TiNi, the Pearson symbol is cP2 (ClCs), and the lattice constant a ₀ =0.301nm, which is a supercooled austenite phase; B19'-TiNi phase is detected at the same time, and the crystal structure parameter a ₀ = 0.2892, b ₀ =0.4108, c ₀ =0.4646, β=97.78 ^o is the martensitic phase, which exists in the as-cast structure due to the high cooling rate of the copper mold.

Figure 2 is the XRD pattern of the suction casting sample after stress loading and fracture. In addition to the typical amorphous diffuse scattering peak, the main crystal phase B19'-TiNi phase precipitated. Tensitic transformation, the amount of martensite precipitation increased significantly.

Figure 3 is the room temperature compressive stress-strain curve of the suction casting sample. The compressive yield strength of the alloy is 1384MPa, the fracture strength is 2256MPa, the compressive strain is 12.2%, and it shows strong work hardening.

Example 2:

Using the same preparation method as in Example 1, the composition of the Ti-based amorphous composite material alloy is:

The atomic percentage is (Ti _0.5 Ni _0.48 Zr _0.02 ) ₈₀ Cu ₂₀ ,

As shown in Figure 1, the as-cast structure of the suction casting sample is an amorphous matrix composite structure, and the main crystal phases are supercooled austenite phase B2-TiNi and martensite phase B19’-TiNi.

As shown in Figure 2, compared with before fracture, part of the austenite transformed into martensite after stress loading, and the amount of martensite precipitation increased significantly.

As shown in Figure 3, the alloy has a compressive yield strength of 1295 MPa, a fracture strength of 2360 MPa, a compressive strain of 11.6%, and exhibits strong work hardening.

Example 3:

Using the same preparation method as in Example 1, the composition of the Ti-based amorphous composite material alloy is:

The atomic percentage is (Ti _0.5 Ni _0.48 Co _0.02 ) ₈₀ Cu ₂₀ ,

As shown in Figure 1, the as-cast structure of the suction casting sample is an amorphous matrix composite structure, and the main crystal phases are supercooled austenite phase B2-TiNi and martensite phase B19’-TiNi.

Compared with before fracture, part of the austenite transforms into martensite after stress loading, and the amount of martensite precipitation increases significantly.

As shown in Fig. 3, the alloy has a compressive yield strength of 1504 MPa, a fracture strength of 2582 MPa, a plastic strain of 15%, and exhibits strong work hardening.

Claims (1)

1. a preparation method for shape memory crystalline phase highly malleablized Ti base amorphous composite, the steps include:

(1) prepare burden:

By atomic percentage, the composition of described Ti base amorphous composite is: (Ti _0.50ni _0.50-ym _y) _100-xcu _x, wherein: M is Co or Zr element, x=5 ~ 33, y=0 ~ 0.25 takes each component;

(2) melting system (Ti _0.50ni _0.50-ym _y) _100-xcu _xmother alloy:

The desired raw material that step (1) claims is put into vacuum high-frequency electromagnetic induction heating furnace;

Regulate the vacuum tightness 2 × 10 of vacuum magnetic suspension smelting furnace ^-3~ 5 × 10 ^-3pa, then fills vacuum tightness to 0.1 × 10 that high-purity argon gas makes vacuum chamber ^-3~ 0.8 × 10 ^-3pa melting, alloy pig melt back at least three times;

(3) copper mold casting prepares amorphous composite sample:

By (Ti prepared by step (2) _0.50ni _0.50-ym _y) _100-xcu _xwater-cooled suspension smelting crucible remelting put into by mother alloy, regulates the vacuum tightness 2 × 10 of vacuum magnetic suspension smelting furnace ^-3~ 5 × 10 ^-3pa, then fills vacuum tightness to 0.1 × 10 that high-purity argon gas makes vacuum chamber ^-3~ 0.8 × 10 ^-3pa;

(4) under induction voltage 5 ~ 10kV, after smelting time 1 ~ 3min, by negative pressure copper mold casting, bar is cast in mother alloy suction;

Described shape memory crystalline phase highly malleablized Ti base amorphous composite is that Ti base noncrystal alloy and the supercooled austenite phase B2-TiNi that can produce deformation induced trans-formation and martensitic phase B19 '-TiNi are composited; In preparation method, by doping and the composition adjustment acquisition different volumes mark supercooled austenite phase B2-TiNi and martensitic phase B19 '-TiNi of alloy, and there is strong amorphous formation ability; The compression yield strength of described matrix material is 1000 ~ 1800MPa, and breaking tenacity is 1400 ~ 2800MPa, and compressive strain is 10% ~ 20%, and shows strong work hardening.