Microstructure And Mechanical Properties Of TiAl Composite Plate Prepared By Cumulative Rolling

With the development of metal composite plate technology,the demand for its performance is higher and higher,and the ensuing difficulties come gradually.The preparation of superfine crystal metal composite sheet with superior performance by cumulative rolling method has been widely concerned.However,in general,after a certain number of cumulative rolling cycles,the hard metal layer will be fractured due to the difference in the flow characteristics of soft and hard metals,resulting in the deterioration of mechanical properties.In the present research,there is no technology that can keep the hard phase metal layer continuous,so it is of certain theoretical value and practical significance to explore the effect of the distribution of the hard phase metal layer in the soft phase metal after fracture on the mechanical properties.In this paper,three groups of Ti-Al composite slabs with different intermediate titanium matrix fracture conditions were prepared by three different technologies.The titanium matrix of the first group of composite slabs was broken irregularly,the titanium matrix of the second group was broken regularly,and the titanium matrix of the third group was not broken.The three groups of composite slabs were overlapped by three layers for five times cumulative stacking.The section morphology observation,tensile testing,tensile fracture retention,combined interface observation and tensile finite element simulation of the composite slabs were carried out.In order to improve the mechanical properties of compound sheet pack rolling,pack rolling composite panels for the proper heat treatment,and analyze the performance of the heat treatment after change.The experimental results show that the long thickness,mechanical properties and tensile fracture morphology of the fractured titanium matrix are similar in the rolled composite plates prepared by regular and irregular fracture composite slabs.However,in the composite plates prepared by the unfractured titanium matrix,the titanium matrix is longer and thinner,the mechanical properties are lower and the tensile fracture morphology of the composite plates prepared by the unfractured titanium matrix and the composite plates prepared by the unfractured titanium matrix and the composite plates prepared by the unfractured titanium matrix are significantly different.However,the differences of the above three points in the composite plates prepared by the unfractured titanium matrix and the composite plates prepared by the unfractured titanium matrix are gradually reduced until they are similar.The observation of Ti-Al bonding interface shows that the difference of bonding interface is not great.The experimental results after heat treatment show that the mechanical properties of the laminated composite plate are improved greatly,the morphological difference at the tensile fracture is reduced,and the thicker diffusion layer appears at the Ti-Al bonding interface and the Ti-Al intermetallic compound is formed which is beneficial to the performance improvement.The tensile process of composite slab was simulated by finite element method,and the mechanical properties of composite slab were analyzed as well as the special phenomena during stretching.The effect of different length and thickness of fractured titanium matrix and distribution in aluminum matrix on the mechanical properties of cumulative laminated composite plate is studied.The simulation results show that the fracture occurs in the aluminum matrix,and the longer length and the closer distribution between the fracture titanium matrix in the loading direction will lead to the premature fracture of the aluminum matrix and the decrease of mechanical properties.