Preparation method of nano-reinforcing metal matrix composite material with high strength and toughness

Abstract

The invention discloses a preparation method of a nano-reinforcing metal matrix composite material with high strength and toughness. The preparation method of the nano-reinforcing metal matrix composite material with high strength and toughness is characterized by comprising the steps of jointly ball-milling pure metal powder, alloy powder thereof, elementary-substance element powder for alloyingand a nano-reinforcing body by adopting variable-speed ball milling so as to obtain I-grade composite powder; then mixing with non-ball-milled pure metal or alloy powder so as to obtain II-grade composite powder; and densifying the obtained II-grade composite powder so as to obtain the nano-reinforcing metal matrix composite material. In the composite material, a non-homogeneous grain structure ofa matrix can promote stress stiffening and work hardening, stress-strain concentration is effectively relieved, and strength and plasticity are synchronously improved. The method is capable of regulating and controlling alloy components of the matrix as needed, wide in application range, and capable of realizing macro-quantitative preparation of bulk composite materials, so that the engineering application of the metal matrix composite material is promoted.

Description

technical field [0001] The invention relates to a preparation method of a high-strength and toughness nano-reinforced metal-matrix composite material, belonging to the technical field of metal-matrix composite materials. Background technique [0002] Metal matrix composites have been commercially applied in many fields such as transportation, aerospace, and electronic communication due to their lightweight structure and excellent heat and wear resistance, electrical and thermal conductivity, and damping and vibration reduction properties. However, SiC, Al 2 o 3 The interface stress concentration generated by the mismatch of modulus and thermal expansion coefficient between the traditional micron reinforcement and the metal matrix will lead to low stress fracture failure, which greatly reduces the plasticity, toughness and damage tolerance of metal matrix composites. In contrast, nano-reinforcements can effectively alleviate thermal mismatch and interfacial stress concentra...

AI Technical Summary

Problems solved by technology

Although the above-mentioned method can prepare nano-reinforced composite materials with non-uniform distribution of matrix grains, it has the following disadvantages: 1) Although high-energy ball milling or low-temperature ball milling can disperse nano-reinforcements, the damage to its structure is also great, especially For nanocarbons (such as carbon nanotubes, graphene, etc.), the intrinsic properties of the reinforcement are significantly reduced; 2) blending the ball-milled powder with the non-ball-milled powder can only obtain a matrix with a bimodal distribution of the grain structure 3) Since the nano-reinforcement is only added into the co-ball milling at the beginning of high-energy ball milling or low-temperature ball milling, it only exists in the fine-grained region, and there is no nano-reinforcement in the coarse-grained region. The space for nano-reinforcement dispersion is reduced, which brings greater challenges to dispersion; 4) The matrix composition is limited. Since the reinforcement and matrix powder need to be subjected to high-energy ball milling or low-temperature ball milling, the strength of the matrix powder cannot be too high. If If the strength of the matrix powder is too high and lacks deformation ability, the structure of the reinforcement will be severely damaged during the deformation process, especially the nano-carbon reinforcement that is sensitive to the structure

Due to the above shortcomings, the mechanical properties of the prepared nano-reinforced metal matrix composites have a strong-plastic inversion relationship in which the strength increases and the plasticity decreases, which restricts the development of engineering applications of such materials.

Images