阅读说明：本技术 一种纳米陶瓷颗粒增强铝基复合材料及其制备方法 (Nano ceramic particle reinforced aluminum matrix composite material and preparation method thereof ) 是由 赵科 刘金铃 于 2019-12-10 设计创作，主要内容包括：本发明公开了一种纳米陶瓷颗粒增强铝基复合材料及其制备方法,包括以下步骤：步骤1：纳米陶瓷颗粒通过高能机械球磨与铝或铝合金粉末混合均匀；步骤2：将步骤1得到的混合粉末烧结即可得到所需复合材料；本发明复合材料中具有高密度层错/微孪晶,使铝基材料保持良好的微观组织热稳定性,在高温下能够有效阻碍位错运动,使得铝基材料即使在400℃以上依然保持高强度,能有效突破目前铝基材料高温强度在200℃以上急剧降低的瓶颈。(The invention discloses a nano ceramic particle reinforced aluminum matrix composite material and a preparation method thereof, and the preparation method comprises the following steps: step 1: uniformly mixing the nano ceramic particles with aluminum or aluminum alloy powder by high-energy mechanical ball milling; step 2: sintering the mixed powder obtained in the step 1 to obtain the required composite material; the composite material has high-density stacking faults/micro twin crystals, so that the aluminum-based material keeps good microstructure thermal stability, and can effectively block dislocation movement at high temperature, so that the aluminum-based material still keeps high strength even at the temperature of more than 400 ℃, and the bottleneck that the high-temperature strength of the conventional aluminum-based material is sharply reduced at the temperature of more than 200 ℃ can be effectively broken through.)

1. A nano ceramic particle reinforced aluminum matrix composite is characterized by comprising an aluminum or aluminum alloy matrix and nano ceramic particles uniformly dispersed in the aluminum or aluminum alloy matrix; the volume fraction of the nano ceramic particles in the composite material is 4-40%; the size of the nano ceramic particles is 10-100 nm, and the distance between particles<150 nm; a semi-coherent interface is formed between the substrate and the nano ceramic particles; having a density of greater than 1 x 10 within the composite³/m²The stacking faults/microtwins are distributed on two crystal planes of the {111} crystal plane family.

2. The nano-ceramic particle reinforced aluminum matrix composite material as claimed in claim 1, wherein the aluminum alloy matrix is one of Al-Cu series aluminum alloy, Al-Mn series aluminum alloy, Al-Si series aluminum alloy, Al-Mg-Si series aluminum alloy, Al-Zn-Mg series aluminum alloy, Al-RE series aluminum alloy, and Al-Fe series aluminum alloy.

3. The nano-ceramic particle reinforced aluminum matrix composite material as claimed in claim 1, wherein the nano-ceramic particles are one of oxide ceramic particles, carbide ceramic particles, nitride ceramic particles and silicide ceramic particles.

4. A method for preparing a nano-ceramic particle reinforced aluminum matrix composite material as claimed in any one of claims 1 to 3, comprising the steps of:

step 1: uniformly mixing the nano ceramic particles with aluminum or aluminum alloy powder by high-energy mechanical ball milling;

step 2: and (3) sintering the mixed powder obtained in the step (1) to obtain the required composite material.

5. The method of claim 4, wherein the sintering in step 2 is one of high vacuum hot pressing sintering and high vacuum hot isostatic pressing sintering.

6. The method for preparing the nano ceramic particle reinforced aluminum matrix composite material as claimed in claim 4, wherein the sintering temperature in the step 2 is 660-730 ℃, and the vacuum degree is 660-730 ℃>1×10^-2Pa, and the heating rate is 5-10 ℃/min.

7. The method for preparing a nano-ceramic particle reinforced aluminum matrix composite material as claimed in claim 5, wherein the load in sintering is 45MPa to 55 MPa.

8. The method for preparing the nano ceramic particle reinforced aluminum matrix composite material as claimed in claim 5, wherein the rotation speed in the high-energy mechanical ball milling in the step 1 is more than 150r/min, and the ball milling time is more than 20 h.

Technical Field

The invention relates to the field of aluminum-based composite materials and preparation thereof, in particular to a nano ceramic particle reinforced aluminum-based composite material and a preparation method thereof.

Background

The block aluminum-based material is widely applied to the fields of aerospace, transportation, military weapons, sports equipment and the like due to the advantages of light weight, high strength, high modulus, excellent wear resistance, reproducibility, low cost and the like, and can be used for aircraft structural parts and engine parts particularly in the field of high-temperature applicationAnd the like. With the continuous pursuit of development requirements of light weight, high energy efficiency, high reliability, emission reduction and the like in modern industry, the titanium-stainless steel is regarded as a most promising substitute for titanium and stainless steel to be applied to high-temperature materials at 300-400 ℃. Currently, the strength of bulk aluminum-based materials decreases dramatically above 200 ℃, which severely limits their use in high temperature environments. In order to improve the high-temperature strength, the existing research mainly adopts means of adjusting alloy components, improving the thermal stability of grain boundaries and precipitation phases, introducing thermally stable second-phase particles such as ceramics and the like to block dislocation movement. For example, the contents of elements such as iron, carbon, titanium, magnesium, manganese, rare earth and the like (CN201711048266.3, CN201811525654.0, CN201910400074.7 and CN201810226104.2) in the alloy are controlled and the process is optimized. However, the strengthening effect of hindering dislocation movement is not ideal due to the fact that a precipitate phase formed by precipitation of the alloy element at high temperature is easy to decompose, coarsen and break, crystal grains grow up, a matrix is softened and the like, and the added alloy element contains rare elements, so that the cost is high, and natural resources are excessively consumed. In addition to alloying, in situ autogenous ceramic particles, e.g. TiB₂SiC, AlN, etc. can also achieve strengthening by hindering dislocation movement (CN201811100536.5, CN201810509603, CN200510029881.0), but still cannot meet application requirements. In addition to dislocation strengthening, twin strengthening is a method for effectively improving the high-temperature strength of metals, and materials such as copper, cobalt, stainless steel and the like can simultaneously improve the strength and plasticity and remarkably improve the high-temperature mechanical property by introducing a layer fault/twin. However, in the case of aluminum, it is difficult to form a stacking fault/twin due to its extremely high stacking fault energy, and stacking fault/twin strengthening is achieved. Although many researchers have studied this problem, it is also possible to generate stacking faults/twins in aluminum under certain specific conditions, such as liquid nitrogen temperature, high strain rate, large strain, nanocrystals, etc.

Disclosure of Invention

The invention provides a nano ceramic particle reinforced aluminum matrix composite material for effectively improving the high-temperature mechanical property and a preparation method thereof.

The technical scheme adopted by the invention is as follows: a nano-class ceramic particles reinforced Al-base composition is prepared from Al or Al-alloy matrix and uniformly dispersed particlesNano-ceramic particles therein; the volume fraction of the nano ceramic particles in the composite material is 4-40%; the size of the nano ceramic particles is 10-100 nm, and the distance between the ceramic particles<150 nm; a semi-coherent interface is formed between the substrate and the nano ceramic particles; having a density of greater than 1 x 10 within the composite³/m²The stacking faults/microtwins are distributed on two crystal planes of the {111} crystal plane family.

Further, the aluminum alloy substrate is made of one of Al-Cu aluminum alloy, Al-Mn aluminum alloy, Al-Si aluminum alloy, Al-Mg-Si aluminum alloy, Al-Zn-Mg aluminum alloy, Al-RE aluminum alloy and Al-Fe aluminum alloy.

Further, the nano ceramic particles are one of oxide ceramic particles, carbide ceramic particles, nitride ceramic particles and silicide ceramic particles.

A preparation method of a nano ceramic particle reinforced aluminum matrix composite material comprises the following steps:

step 1: uniformly mixing the nano ceramic particles with aluminum or aluminum alloy powder by high-energy mechanical ball milling;

step 2: and (3) sintering the mixed powder obtained in the step (1) to obtain the required composite material.

Further, the sintering in the step 2 is one of high vacuum hot pressing sintering and high vacuum hot isostatic pressing sintering.

Further, the sintering temperature in the step 2 is 660-730 ℃, and the vacuum degree is>1×10^-2Pa, and the heating rate is 5-10 ℃/min.

Further, the load during sintering is 45MPa to 55 MPa.

Further, in the step 1, the rotating speed in the high-energy mechanical ball milling is more than 150r/min, and the ball milling time is more than 20 h.

The invention has the beneficial effects that:

(1) the invention provides a method for presetting the stacking fault/micro twin crystal in the aluminum matrix with simple equipment requirement and convenient operation, good repeatability and low cost;

(2) the dislocation/microtwinite in the composite material not only enables the aluminum-based material to keep good microstructure thermal stability, but also can effectively block dislocation movement at high temperature, so that the aluminum-based material still keeps high strength even at the temperature of more than 400 ℃, and the bottleneck that the high-temperature strength of the aluminum-based material is sharply reduced at the temperature of more than 200 ℃ at present can be effectively broken through;

(3) compared with the alloying method, the method does not depend on the addition of rare elements such as rare earth and the like, saves natural resources and reduces the cost.

Drawings

Fig. 1 is a microstructure of the composite material prepared in example 1.

Fig. 2 is a graph of the true stress-strain curves of the composite material prepared in example 1 at different temperatures.

FIG. 3 is a comparison of the high temperature mechanical properties (strength-strain) of the composite material prepared in example 1 with those of a conventional aluminum-based material.

Detailed Description

The invention is further illustrated with reference to the following specific embodiments and the accompanying drawings.

A nano ceramic particle reinforced aluminum matrix composite comprises an aluminum or aluminum alloy matrix and nano ceramic particles uniformly dispersed in the aluminum or aluminum alloy matrix; the volume fraction of the nano ceramic particles in the composite material is 4-40%; the size of the nano ceramic particles is 10-100 nm; a semi-coherent interface is formed between the substrate and the nano ceramic particles; having a density of greater than 1 x 10 within the composite³/m²The stacking faults/microtwins are distributed on two crystal planes of the {111} crystal plane family. The nano ceramic particles are uniformly dispersed in the aluminum-based crystal grains, the particle spacing is in the nano scale (less than 150nm), and the nano ceramic particles can be correspondingly adjusted according to specific performance requirements.

The aluminum alloy substrate is one of Al-Cu aluminum alloy, Al-Mn aluminum alloy, Al-Si aluminum alloy, Al-Mg-Si aluminum alloy, Al-Zn-Mg aluminum alloy, Al-RE aluminum alloy and Al-Fe aluminum alloy. The nano ceramic particles are one of oxide ceramic particles, carbide ceramic particles, nitride ceramic particles and silicide ceramic particles.

A preparation method of a nano ceramic particle reinforced aluminum matrix composite material comprises the following steps:

step 1: uniformly mixing the nano ceramic particles with aluminum or aluminum alloy powder by high-energy mechanical ball milling;

step 2: and (3) sintering the mixed powder obtained in the step (1) to obtain the required composite material. The sintering is one of high vacuum hot pressing sintering and high vacuum hot isostatic pressing sintering. The sintering temperature is 660-730 ℃, and the vacuum degree is more than 1 multiplied by 10^-2Pa. The load in sintering is 45 MPa-55 MPa.

By adding a certain amount of nano-ceramic particles to aluminum and aluminum alloys, the aluminum or aluminum alloys are divided into a series of nano-regions by the nano-ceramic particles. By a high temperature high vacuum semi-solid or liquid consolidation process, (locally) molten aluminum or aluminum alloy grows along a specific crystallographic orientation with nano-ceramic particles as a substrate, thereby forming a semi-coherent interface between the two. High strain energy is accumulated at the semi-coherent interface, a strong strain field is provided, and the thermal mismatch and modulus mismatch of aluminum or aluminum alloy and ceramic particles enable local high stress and stress gradient to exist in crystal grains, the stress gradient can effectively reduce the stacking fault energy of the aluminum, in addition, the high sintering temperature can aggravate the improvement of the stress, meanwhile, the dislocation formation is inhibited by the aluminum or the aluminum alloy in a nanometer area, which is more beneficial to the formation of incomplete dislocation, the local high stress near the interface can meet the critical stress for forming the incomplete dislocation, thus the dislocation is formed by emitting the incomplete dislocation, and the dislocation can be further stacked to form a twin crystal. Thus, high-density stacking faults/twin crystals are preset in the aluminum by adding nano ceramic particles and combining a high-temperature high-vacuum semi-solid or liquid consolidation process. The dislocation movement is effectively blocked by utilizing the good thermal stability of a layer fault/twin crystal interface, and the dislocation in the aluminum or aluminum alloy is inhibited from being recombined and annihilated by cross sliding and climbing at high temperature, so that the thermal stability of the microstructure of the aluminum or aluminum alloy is kept, and the high-temperature mechanical property of the aluminum or aluminum alloy is effectively improved.