Disclosure of Invention
The invention aims to provide an endogenous high-entropy alloy-based composite material prepared by a vacuum induction melting technology and a method thereof, and the process is simple to operate, safe, reliable, energy-saving, time-saving, environment-friendly and regular and fine TiB2The reinforced particles are generated by in-situ reaction, the surface is free from pollution, and the interface is clean.
The technical solution for realizing the purpose of the invention is as follows: the high-entropy alloy-based composite material is an endogenous composite material, takes AlMFeNiCu high-entropy alloy as a matrix phase and Takes (TiC)xFor the reinforcing phase, note (TiC)x/(AlMFeNiCu)1-xWherein M is Si or Co, and x is 0.1-0.2.
The method for preparing the endogenous high-entropy alloy-based composite material comprises the following steps:
firstly, weighing high-purity Al, M, Ni, Ti, Cu and Fe metal particles according to the composition of a target composite material, and pretreating the surfaces of the metal particles to remove surface oxide layers;
step two, preparing a reinforcement test block: weighing high-purity Ti powder, C powder and Fe powder according to the composition of a target composite material, ball-milling, mixing, drying, and preparing a reinforcement test block under certain pressure;
thirdly, the prepared sample is processed according to the formula (TiC)x/(AlMFeNiCu)1-xAl particles, a reinforcing body test block, Ni particles, Fe particles, M particles and Cu particles are sequentially added into the corresponding raw materials, and the vacuum degree reaches 10-3When the pressure is above Pa, introducing argon to keep the pressure not more than 10-1Pa, electrifying for induction melting, preliminarily heating to 950-1050 ℃, observing reaction in the furnace in an observation window, heating to 1450-1550 ℃, further heating to 2000-2200 ℃ when a test block to be reacted is basically melted, melting for 8-12 minutes, and repeatedly melting for 2-3 times;
step four, heat preservation and cooling: and after the temperature is preserved for 3-8 minutes, pouring the reaction molten alloy into a water-cooled copper crucible, and attaching the reinforcement particles to the surfaces of the fine-grain particles in the matrix for growing to obtain the fine-grain high-entropy alloy-based composite material.
Preferably, in the second step, the ball milling rotating speed is 250-300 p.r.m; the ball milling time is 6-8 h; the ball-to-material ratio (mass ratio of balls to powder) is 4.5: 1.
preferably, in the second step, the drying temperature is 110-120 ℃, the drying time is 2 hours, and the blank sample is extruded under 180 MPa.
Compared with the prior art, the invention has the following remarkable advantages: (1) the induction melting synthesis activation energy is lower than that of the conventional heating mode, the reaction temperature is lower, the reaction is rapid, the process operation is simple, safe and reliable, energy and time are saved, and the environment is friendly. (2) Because the temperature rise rate is high and the reaction process is short, the coarsening of the structure and the dendrite segregation are inhibited, the structure can be obviously refined by the method, meanwhile, because the reaction releases heat quickly, the self-stirring can be carried out, the high heat generated by the reaction can effectively purify the matrix, and the improvement of the performance of the material is facilitated. (3) The high-entropy alloy matrix phase generated by the reaction has amplitude modulation decomposition and lattice distortion effects so as to prevent the material from generating stress relaxation deformation due to lattice movement. (4) The high-entropy alloy-based composite material generated by the reaction has a single face-centered cubic structure, the material strength and the shaping are good, the structure is simple, no complex intermetallic compound phase is generated, and a regular single-phase or double-phase solid solution structure is formed.
Detailed Description
Example 1: (TiC)0.1/(AlSiFeNiCu)0.9Composite material
The method for preparing the endogenous high-entropy alloy-based composite material by vacuum induction melting specifically comprises the following steps:
(1) high-purity Al, Si, Ni, Fe and Cu metal particles are weighed according to the volume fraction of the reinforcement body of 10 percent, the surfaces of the metal particles are pretreated before use, a surface oxidation layer is taken out, and the oxidation layer is volatilized at high temperature to influence the smelting quality.
(2) Preparing a reinforcement test block: weighing high-purity Ti powder C and Fe powder according to the volume fraction of the reinforcement, and mixing to obtain ball powder with the mass ratio of 4.5: 1; the ball milling speed is 250-300 p.r.m; the ball milling time is 6-8 h. Drying at 110-120 deg.c for 2 hr, and extruding under 180MPa to form blank.
(3) Vacuumizing and introducing protective gas: after cooling water is boiled, the mixture is pumped by a mechanical pump to be vacuum<5Pa, then pumping to 10 ℃ by using a molecular pump-4Pa. After the pressure is stabilized, introducing protective gas (argon) to maintain the pressure at 10-1Pa or so, and then vacuumizing to 10 DEG-4Introducing argon after PaMake the air pressure reach 10-1And repeatedly applying Pa for 2-3 times.
(4) Adjusting the heating rate: 1. a temperature-rising reaction stage: firstly, adjusting output high-frequency current 400A, when the crucible is lightened, adjusting the output current to 350A, 2, and an enhancement body generation stage: after 5 minutes, an in-situ reaction occurs, heat is released to emit white light, and then the temperature is immediately raised to 1500 ℃ so that the reinforcing body test block is melted into the matrix. 3. Alloying: and adjusting the output current to enable the temperature to reach 1500-2000 ℃, melting and alloying the metal particles, rolling and stirring the alloy system from inside to outside in the induction self-stirring process, and uniformly distributing the reinforcement in the high-entropy alloy matrix.
(5) Step four, heat preservation and cooling: after the temperature is preserved for 5 minutes, the reaction melting alloy is poured into a water-cooled copper crucible, and the reinforcement particles are attached to the surfaces of the fine crystal particles in the matrix for growing to obtain the fine crystal high-entropy alloy-based composite material.
XRD detection is carried out on a sample, the figure 1 shows that the obtained high-entropy alloy-based composite material is a TiC-reinforced high-entropy alloy-based composite material, a part of SiC reinforcing phase and SEM (scanning electron microscope), EDS (electron Desorption) analysis sample composition is shown in the figure 2, the figure 3 shows that a main reinforcement is TiC, the growth is regular, the distribution is uniform, and a matrix is a two-phase structure rich in Fe, Ni and Si and rich in Al, Ni and Cu.
Example 2: (TiC)0.2/(AlSiFeNiCu)0.8Composite material
(1) Weighing high-purity Al, Si, Ni, Fe and Cu metal particles according to the volume fraction of the reinforcement body of 20%, pretreating the surfaces of the metal particles before use, taking out a surface oxidation layer, and volatilizing the oxidation layer at high temperature to influence the smelting quality.
(2) Preparing a reinforcement test block: weighing high-purity Ti powder C and Fe powder according to the volume fraction of the reinforcement, and mixing to obtain ball powder with the mass ratio of 4.5: 1; the ball milling speed is 250-300 p.r.m; the ball milling time is 6-8 h. Drying at 110-120 deg.c for 2 hr, and extruding under 180MPa to form blank.
(3) Vacuumizing and introducing protective gas: after cooling water is boiled, the mixture is pumped by a mechanical pump to be vacuum<5Pa, and then vacuumizing by using a molecular pumpTo 10-4Pa. After the pressure is stabilized, introducing protective gas (argon) to maintain the pressure at 10-1Pa or so, and then vacuumizing to 10 DEG-4Introducing argon after Pa to make the pressure reach 10-1And repeatedly applying Pa for 2-3 times.
(4) Adjusting the heating rate: 1. a temperature-rising reaction stage: firstly, adjusting output high-frequency current 400A, when the crucible is lightened, adjusting the output current to 350A, 2, and an enhancement body generation stage: after 5 minutes, an in-situ reaction occurs, heat is released to emit white light, and then the temperature is immediately raised to 1500 ℃ so that the reinforcing body test block is melted into the matrix. 3. Alloying: and adjusting the output current to enable the temperature to reach 1500-2000 ℃, melting and alloying the metal particles, rolling and stirring the alloy system from inside to outside in the induction self-stirring process, and uniformly distributing the reinforcement in the high-entropy alloy matrix.
(5) Step four, heat preservation and cooling: after the temperature is preserved for 5 minutes, the reaction melting alloy is poured into a water-cooled copper crucible, and the reinforcement particles are attached to the surfaces of the fine crystal particles in the matrix for growing to obtain the fine crystal high-entropy alloy-based composite material.
It can be seen from fig. 4a that the microstructure of the sample prepared by the reaction has good compactness, and the reinforcing body particles are uniformly distributed in the matrix, and it can be seen from fig. 4b that the reinforcing body grows completely and the combination between the reinforcing body and the matrix is good.
Example 3: (TiC)0.1/(AlCoFeNiCu)0.9Composite material
(1) High-purity Al, Co, Ni, Fe and Cu metal particles are weighed according to the volume fraction of the reinforcement body of 10%, the surfaces of the metal particles are pretreated before use, a surface oxidation layer is taken out, and the oxidation layer is volatilized at high temperature to influence the smelting quality.
(2) Preparing a reinforcement test block: weighing high-purity Ti powder C and Cu powder according to the volume fraction of the reinforcement, and mixing to obtain ball powder with the mass ratio of 4.5: 1; the ball milling speed is 250-300 p.r.m; the ball milling time is 6-8 h. Drying at 110-120 deg.c for 2 hr, and extruding under 180MPa to form blank.
(3) Vacuumizing and introducing protective gas: after cooling water is boiled, the mixture is pumped by a mechanical pump to be vacuum<5Pa, pumping with molecular pumpHollow to 10-4Pa. After the pressure is stabilized, introducing protective gas (argon) to maintain the pressure at 10-1Pa or so, and then vacuumizing to 10 DEG-4Introducing argon after Pa to make the pressure reach 10-1And repeatedly applying Pa for 2-3 times.
(4) Adjusting the heating rate: 1. a temperature-rising reaction stage: after charging, firstly adjusting output high-frequency current 400A, when the crucible is shiny, adjusting the output current to 350A, 2, and an enhancement body generation stage: after 5 minutes, an in-situ reaction takes place, heat is released to give off white light, and then the temperature is immediately raised to 1700 ℃ to melt the reinforcement test block into the matrix. 3. Alloying: adjusting output current to enable the temperature to reach 1800-2000 ℃, melting and alloying metal particles, wherein in the process of induction self-stirring, the alloy system is stirred in a rolling manner from inside to outside, and the reinforcement bodies are uniformly distributed in the high-entropy alloy matrix.
(5) Step four, heat preservation and cooling: after the temperature is preserved for 5 minutes, the reaction melting alloy is poured into a water-cooled copper crucible, and the reinforcement particles are attached to the surfaces of the fine crystal particles in the matrix for growing to obtain the fine crystal high-entropy alloy-based composite material.
As can be seen from the SEM picture of the composite material in fig. 5, the black regular objects are reinforcement particles TiC. The dark areas are Co-rich phases and the matrix phase is white areas.