Insight Into The Preparation,Microstructure And Mechanical Properties In Dual-phase Reinforced TC4 Composites

Titanium alloys are widely used in airframes,turbine blades,and aerospace engines due to their low density and high specific strength.As modern aerospace continues to develop,researchers and practitioners are focused on the research and development of lightweight,high-strength,and medium-tough aerospace materials.However,traditional titanium and titanium alloy materials are generally unable to meet the requirements for ultra-high strength due to their low modulus of elasticity.To further improve the strength and plasticity of titanium alloys,titanium matrix composites（TMCs）with a high modulus of elasticity have become recognized as promising new aerospace materials.In this paper,we investigated the effect of the amount and content of reinforcement on the strength and plasticity changes of TMCs in different states.The main studies are as follows:（1）We investigated the effects of the quantity and content of reinforcement on the strength and plasticity of sintered TC4/Ti B₂/C composites.Among them,the titanium alloy matrix has a Widmannstatten structure,while the reinforcement has a network-like structure.Our findings indicate that with the increase of reinforcement content,the overall grain size of the composites was refined,and the strength increased while the plasticity decreased rapidly.However,with the increase of reinforcement quantity,the strength of the composites further increased while the plasticity decreased slowly.The best tensile strength of the composites reached 1144.6MPa,while the elongation was 10.1%.Increasing the reinforcement content can improve the strength of the composites,while the dual-phase reinforced can improve both the strength and plasticity of the composites.（2）We investigated the effects of the quantity and content of reinforcement on the strength and plasticity of hot-rolled TC4/Ti B₂/C composites.In these composites,the reinforcements were aligned directionally,and the grains of the composites were further refined.Our findings indicate that the strength of the composites increased and the plasticity decreased with the increase of the reinforcement content,while the strength of the composites initially increased and the plasticity increased,and then decreased with the increase of the content of reinforcements.To find the optimal performance,we found that the tensile strength of the composite with a total reinforcement content of 0.8 wt%can reach 1586.3 MPa and the elongation is 9.7%by synergistic reinforcement of the two phases.The results show that there is a close synergistic effect between the reinforcements in the hot rolled state dual-phase reinforced composites,which further enhances the performance of the titanium matrix composites.The hot rolling process is an effective way to further improve the strength and plasticity of the composites.（3）We investigated the strength and plasticity changes of dual-phase reinforced TC4/Ti B₂/C composites in the hot-rolled state after heat treatment.Our findings indicate that the crystalline band axes of the titanium alloy matrix and the ceramic phase in the solution hot-rolled state composites were parallel,forming a close in situ growth of the matrix and the reinforcement.With the increase of the reinforcement content,the strength of the composites first increased and then decreased,while the plasticity gradually decreased.We found that when the total reinforcement content reached 0.8 wt%,the tensile strength of the composites reached 1658.5 MPa,while the elongation was 6.7%.The results suggest that the solution hot-rolled is a viable option to further improve the strength of the composites.