Research On The Effect Of Woven Fabric Structure On Microstructure And Mechanical Properties Of 2.5D-C_f/Al Composites

Continuous carbon fiber reinforced aluminum alloy composites(C_f/Al composites)with high strength,high modulus,low thermal expansion coefficient and good heat resistance and anti-aging properties,shows great potential application in the field of aerospace and other defense technology.Three dimensional angle interlock(2.5D)woven fabric reinforced composite has good structural integrity and each direction property design feasibility,which is a new structure of composite in recent years,at present,the research was focused on the field of 2.5D woven fabric reinforced resin matrix and ceramic matrix composites,however,there were few reports on 2.5D woven fabric reinforced aluminum matrix composites and only limited to material preparation,lack of research on the influence of woven fabric structure on its macro mechanical properties and fracture failure mechanism,it is difficult to provide theoretical guidance for the preparation process and woven fabric structure design.2.5D woven fabric C_f/Al composites(2.5D-C_f/Al composite)with ZL301 as matrix alloy and 2.5D woven fabric shallow-bend joint woven,shallow-straight joint woven and layer linking structure as reinforcement were fabricated by the vacuum assisted pressure infiltration method.The effects of woven fabric structure on the density and microstructure of 2.5D-C_f/Al composites were studied,analyzed the influence of woven fabric structure on the composite warp/weft tensile and bending mechanical properties;focus on the shallow-bend joint woven structure of 2.5D-C_f/Al composites,the relationship between woven fabric warp/weft fiber ratio and mechanical properties of the composites was studied.Based on the mechanical behavior of composite tensile deformation and fracture morphology analysis explored the macro and micro fracture and failure mechanism,the main conclusions are as follows:The 2.5D-C_f/Al composite fabric structure can be maintained well by vacuum assisted pressure infiltration,three kinds of composite fiber has a small amount of segregation;the average density of the composites prepared by shallow-bend joint woven,shallow-straight joint woven and layer linking structure was 98.5%,97.8%and 97.6% respectively,the fabric structure has not a significant influence on thecomposites density;The composite interfacial product was Al4C3,which was short rod with rhombohedral crystal structure,Al4C3 phase approximate content of up to 5.8%.The warp ultimate tensile strength of shallow-bend joint woven,shallow-straight joint woven and layer linking structure of 2.5D-C_f/Al composites was 380.61 MPa,414.51 MPa,391.33 MPa,and the weft ultimate tensile strength was 268.25 MPa,247.14 MPa,244.65 MPa,respectively,the shallow-bend joint woven composite has a more balanced warp/weft tensile performance than the shallow-straight joint woven and layer linking structure composites;three kinds of woven fabric composite warp ratio of tensile strength and theoretical strength was higher than the weft,to show that warp has a better bearing capacity;composite tensile fracture can be found some holes when the fiber pulled out from the matrix,but the warp tensile fracture is more uneven than the weft,and the fibers were pulled out obviously.The warp bending strength of shallow-bend joint woven,shallow-straight joint woven and layer linking structure of 2.5D-C_f/Al composites was 385.93 MPa,454.74 MPa,429.15 MPa,and the weft bending strength was 360.03 MPa,371.57 MPa,401.23 MPa,respectively,three kinds of woven fabric structure composites warp bending strength is higher than that of the weft direction;the woven fabric structure has a more significant effect on the composite flexural strength,while compared to the tensile mechanical properties,woven fabric structure has a weak effect on composites warp/weft bending mechanical properties.The shallow-bend joint woven 2.5D-C_f/Al composite micro infiltration defects increased with the increase of the warp/weft fiber content;under the condition of certain volume fraction,the warp and weft tensile properties showed a tendency to increase first and then decrease,the composites show a significant tensile nonlinear mechanical behavior in both warp direction and the weft direction;according to the characteristics of tangent modulus the tensile deformation process can be divided into three stages: the initial elastic deformation stage,the middle elastoplastic deformation stage and the final fracture stage.Composite warp tensile failure mechanism is the warp breaking and with a small amount of fiber in weft bundles fracture,while the weft tensile fracture and failure mechanism is the weft breaking and warp transverse cracking between bundles.