A Study On The Mechanical Properties And Damage Evolution Behaviors Of Ti/Al₃Ti Laminate Composite

With the innovation of science and technology,the requirements for materials in the fields of aerospace,weapons equipment and others are getting higher and higher.How to make the materials have excellent performance,such as light weight,high temperature resistance and high strength is a hot topic for material researchers in many fields.In recent years,the metal/intermetallic laminate composite materials have been developed by researchers under the inspiration of shell structure.Among them,Ti/Al₃Ti laminate composite has bright prospect in the field of protection due to its low density,high strength and excellent impact resistance.Ti/Al₃Ti laminate composite was prepared by hot pressing sintering technology in this thesis.Metallographic microscope,Scanning electron microscope,X-ray diffractometer and so on were used to characterize the microstructure of the material and analyze its tissue components.The results showed that the Ti/Al₃Ti laminate composite has compact structure and good bonding.The hardness and fracture toughness of the material were tested by micro-hardness tester,and the results showed that the fracture toughness value at the interface is more than twice that of the matrix value of Al₃Ti.The microscopic crack was observed by microscope,the influence of interface on crack propagation behavior was discussed,and the toughening mechanism of the material was analyzed.The mechanical responses and failure modes of Ti/Al₃Ti under compression and bending loads were studied by Instron universal testing machine.In order to study the enhancement effect of Ti layer on intermetallic compound Al₃Ti,compression test and three-point bending tests were carried out on single-phase Al₃Ti under the same experimental conditions.The results showed that the bending strength of intermetallic compound Al₃Ti increased by 1.74 times after the introduction of ductile Ti layer.Based on the experimental study of the interface properties of materials,the zero-thickness interface model was established according to the physical characteristics of the interface layer and the traditional strength failure theory.The calculation error caused by ignoring the interface of existing Ti/Al₃Ti numerical model was compensated.The ballistic impact experimental model of Ti/Al₃Ti laminate composite was established using LS-Dyna finite element simulation software and the damage processes were simulated when Ti/Al₃Ti laminate composite was penetrated by bullet.The influence of interface failure on the failure form of Ti/Al₃Ti laminate composite under impact loading was then analyzed.