Ti-Al-Nb based composite material and preparation method thereof

Abstract

The invention discloses a Ti-Al-Nb-based composite material and a preparation method thereof, the material comprises a Ti-Al-Nb alloy matrix and 1.5%-10% by volume of TiB whiskers, the matrix comprises 18-25 at% of Al, 12-27 at% of Nb and the balance Ti, the structure form of the matrix is that a needle-shaped O phase is distributed in a deformed non-equiaxial B2 phase matrix, and the average value of the ratio of the long axis to the short axis of B2 crystal grains is larger than or equal to 1.5; the TiB crystal whiskers are distributed at the B2 phase crystal boundary in a complete and unbroken form, are connected with B2 crystal grains on the two sides in a pin type structure, and pin the B2 phase crystal boundary. The matrix alloy of the composite material is deformed and has streamline characteristics; the reinforcement TiB whisker is complete, free of fracture and uniform in distribution; the TiB crystal whiskers with the high length-diameter ratio effectively pin a deformation matrix grain boundary, so that the grain boundary pinning strengthening effect and the intragranular deformation strengthening effect have a synergistic effect, and the thermal strength performance of the material is greatly improved.

Description

technical field [0001] The invention belongs to the field of metal-based composite materials, and in particular relates to a Ti-Al-Nb-based composite material and a preparation method thereof. Background technique [0002] The three-principal Ti-Al-Nb alloy is a kind of structural material with excellent high-temperature comprehensive performance matching. It is an important candidate material for components such as aero-engine compressor discs, blisks, casings, and stator rings. It is expected to replace nickel-based superalloys. , to achieve a substantial reduction in engine weight, thereby improving the overall level of the engine. [0003] Ti-Al-Nb alloy has better process plasticity because it contains a certain amount of B2 phase, which is beneficial to the forming of components. However, the self-diffusion rate of the B2 phase is very high, and the diffusion rate of the grain boundary is higher, which is very unfavorable for high-temperature creep, durability and oth...

AI Technical Summary

Problems solved by technology

Although the introduction of a ceramic reinforcement phase can make the material have higher performance potential, it brings new problems: one is the structure control problem of poor reinforcement distribution uniformity; the other is the forming problem of large deformation resistance and poor process plasticity; The third is the problem that the deformation strengthening of the matrix and the reinforcing effect of the reinforcement are difficult to work synergistically, because even if the composite material undergoes macroscopic deformation without cracks, the matrix can be deformed and strengthened, but the whisker reinforcement basically does not have the ability to coordinate deformation. Either a fracture occurs or the nearby matrix cracks. The fracture leads to a decrease in the aspect ratio of the whiskers. The fractured surface of the whisker and the cracked surface of the matrix are newly introduced micro-defects, which greatly reduce the enhancement benefit.

[0007] Therefore, the above problems have always been the bottlenecks that cannot be solved by the existing technologies in the industry, and are also technical difficulties that must be overcome in the application of metal matrix composites.

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