Preparation method of TiB nano-reinforced titanium-based composite material

Abstract

The invention relates to a preparation method of a TiB nano-reinforced titanium-based composite material, and belongs to the field of metal-based composite materials. According to the method, the composite material is prepared through ball milling, spark plasma sintering and hot rolling. The original powder is prepared through ball milling, the advantages that the sintering efficiency of the discharge plasma is high, and the external pressure and the sintering atmosphere can be controlled are utilized, so that under the low sintering temperature and the high pressure, and on the premise that the TiB2 particles and the surrounding titanium or titanium alloy matrix do not generate in-situ reaction, a sintering block body with high compactness is prepared; and finally, the TiB2 particles in the sintered block body are subjected to in-situ reaction with the surrounding titanium or titanium alloy matrix through hot rolling to form whiskers, and meanwhile, the crystal grains of the matrix are deformed, the porosity in the structure is reduced, and the strength and the plasticity of the composite material are improved. The TiB nano crystal whisker generated in situ in the method is cleanin surface and is uniformly distributed in a matrix and free of agglomeration, has good interface bonding and lattice relationship with the titanium matrix, and can effectively refine matrix crystal grains.

Description

technical field [0001] The invention relates to a preparation method of a TiB nano-reinforced titanium-based composite material, belonging to the field of metal-based composite materials. Background technique [0002] Titanium and titanium alloys have low density (about 4.5g / cm 3 ), high strength, high and low temperature resistance, corrosion resistance and non-magnetic characteristics, through optimization of alloy elements and modern heat treatment process, its strength limit can reach 150kg / mm 2 Above, the specific strength is about 33, while for steel, it needs to be as high as 255kg / mm 2 ~265kg / mm 2 In order to achieve such a high specific strength. Titanium and titanium alloys are widely used, such as aerospace, automotive equipment and military, almost involving all sectors of the national economy and various fields of modern technology, and play an important role in promoting the development of industry and the improvement of productivity. [0003] However, with...

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Problems solved by technology

However, these methods are complicated in process. During the processing of ceramic reinforced titanium matrix composites, due to the high activity of titanium, it is very easy to oxidize, resulting in high porosity of the product, which has become a major obstacle to the application of ceramic reinforced titanium matrix composites.

Secondly, the conventional sintering method requires a long sintering time. As the sintering time prolongs, the TiB whiskers generated by the in-situ reaction begin to coarsen, and the aspect ratio also begins to decrease.

Korean scholar Min Young Koo's research shows that the reduction of the aspect ratio of TiB whiskers will lead to a decrease in the load transfer strengthening effect of the reinforcement phase, thereby reducing the mechanical properties of TiB-reinforced titanium matrix composites.

In addition, when boride is used as raw material, the reaction between boride and titanium powder particles is faster, and the diffusion of boron atoms is not sufficient during the sintering process. In the later stage of the reaction, due to the large amount of TiB generated on the surface of boride, making The concentration gradient of boron atoms becomes smaller, and it is easy to form a mixed agglomeration zone between TiB and incompletely reacted boride raw materials

Agglomerates are similar to irregular particles, and the strengthening effect is low, which in turn weakens the strengthening effect of TiB-reinforced titanium matrix composites

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