| As a new type of high-temperature structural material,Ti2 Al Nb alloy is good at hightemperature strength,high-temperature creep resistance,fatigue and other properties,and the introduction of TiB reinforced phase can further improve its various properties.Studies have shown that the quasi-continuous network distribution of short fiber TiB in composite materials can significantly improve the strengthening effect of reinforcements and the strength and plasticity of Ti-based composite materials.However,its network distribution in Ti2 Al Nb-based alloys has a bearing on the performance of composite materials has not been reported.Therefore,the study of mesh TiB/Ti2AlNb composites is of great significance.In this paper,the tensile properties of mesh TiB/Ti2AlNb composites with different process parameters are studied by finite element simulation,and the composite materials are determined by orthogonal experiments.The best process parameters.In this paper,the finite element method is used to establish a two-dimensional model of the TiB/Ti2AlNb composite material in the micrometer scale.By simulating the uniaxial room temperature tensile process,the composite material with different network structure（d value）,different TiB content and deformation amount is studied for their influence of macro stress,stress distribution and fracture behavior.Finally,some results are analyzed by orthogonal test method,and the following conclusions were obtained:（1）For reticulated TiB/Ti2AlNb composites without thermomechanical processing,the yield strength increases with the increase of TiB content;as the d value increases,the yield strength of the composites fluctuates,and the minimum at d=0μm,While d=25μm and 100μm is larger.The fracture strength generally decreases with the increase of d value.And when the d value is small,the fracture strength of the composite decreases with the increase of TiB content.When the d value is large,the fracture strength of the composite material fluctuates with the change of TiB content.（2）When the content of TiB in the TiB enrichment zone is >15 vol%,the stress concentration zone of the networked TiB/Ti2AlNb composite is connected to each other near the TiB,showing a clear network structure,and the fracture is mainly transgranular fracture;When the content of TiB in the TiB enrichment zone is about 10-15 vol%,the network structure of the stress concentration zone during the tensile process of the composite material is not obvious,and there are both transgranular and intergranular fracture modes;When the content of TiB in the TiB enrichment zone is <10 vol%,the stress concentration zone is dispersed and does not exhibit a network structure,and the fracture is not affected by the network structure.In general,the cracks form an angle of 45o with the tensile direction.（3）Compression deformation has little effect on the elastic modulus and yield strength of the networked TiB/Ti2AlNb composite,but as the amount of deformation increases,the fracture strength of the elongation of the composite increases.During the tensile process,the stress will be a network structure when the local content of TiB is >10 vol%,and the fracture is mainly transgranular fracture.（4）For the yield strength of the networked TiB/Ti2AlNb composite,the order of influence degree of different process parameters is TiB content,deformation,and d value,but the impact of the three are not significant.For the fracture strength,the primary and secondary order of the influence of each process parameter is the d value,TiB content and deformation amount,where the d value has a significant effect,the TiB content has a certain influence and the deformation amount has little effect.Regarding elongation,various factors have significant effects,especially the d value and TiB content,which have a very significant effect on the elongation of the composite material.Finally,combined with experiments,the preferred process parameter was determined to be a 70% deformation d=25μm mesh 2vol%TiB/Ti2AlNb composite. |
