Effect Of Melt Hydrogenation On The Interface Between Reinforcements And Matrix Of (TiC+TiB)/Ti-6Al-4V Composites

Particle-reinforced titanium matrix composites exhibit excellent performance in terms of high temperature resistance,oxidation resistance,and weight reduction.They are expected to be well used in the fields of hypersonic vehicles and next-generation weapons.However,the existing titanium matrix composites still have problems such as difficulty in post-processing and the improvement of the interface between the reinforcement and the matrix.In recent years,some scholars have found that melt hydrogenation can improve the processing properties of titanium alloys,and can inhibit the interface reaction and improve the interface.Therefore,this study attempts to apply melt hydrogenation to improve the interface between matrix and reinforcement,and to explore the effect of melt hydrogenation on the interface of(TiC+TiB)/Ti-6Al-4V composite matrix and reinforcement,the volume fraction of ceramic particales was 5%.The(TiC+TiB)/Ti-6Al-4V composites were prepared by Ingot Metallurgy in a hydrogen-argon mixed atmosphere with different hydrogen partial pressures.The effects of melt hydrogenation on composite reinforcements and matrix of compositesand the influence of the phase interface,the influence of the microstructure and interface after the tensile deformation were studied,the crack initiation and expansion model near the interface is analysed.It was found that after melt hydrogenation,the coarse slat-like structure of the matrix of the composites was gradually replaced by the fine basket structure,and the interlamellar spacing of the α-phase was also significantly reduced.Melt hydrogenation significantly refines the structure of the composite matrix and increases the β phase content of the composite matrix.The morphology of the TiC reinforcement is mainly granular,equiaxed or nearly equiaxed,and the TiB reinforcement is mainly elongated,needle-like and tubular.Hydrogen increased the length-diameter ratio of TiB and the size of TiC.As the hydrogen content increases,the distribution of the ceramic particales in the composites changed from homogeneous dispersion distribution to approxiamate network distribution.In addition,as the hydrogen content increases,the nanohardness of each phase in the composites tends to decrease first and then increase.It is found that melt hydrogenation reduces the occurrence of cracks at the interface after deformation,and improves the bonding strength between the reinforcement and the matrix in the composite.After hydrogenation,the load on the composite can be better transmitted to the reinforcement until the reinforcement begins to break,so the strength of the material is increased.The crack is more likely to sprout in the vicinity of the reinforcement or the interface,and the direction of propagation of the crack is expanded from a direction parallel to the interface of the reinforcement to a direction extending through the reinforcement.As the hydrogen content increases,the arrangement of atoms at the interface between the reinforcemens and the matrix becomes clearer and more ordered,and hydrogen promotes a more ordered arrangement of atoms at the interface between the reinforcement and the matrix in the composite,thereby,the interface is better combined,and melt hydrogenation can also reduce the stacking fault inside the TiB reinforcement.In this paper,the variation of the elements in the interface is characterized by the distance required from the change of the element to the relative stability during the scanning process from the matrix to the reinforcement,and this distance is called the thickness of the interface "transition layer".The result shows that as the hydrogen content increases,the "transition layer" thickness at the interface between the reinforcement and the matrix decreases.