Research On Fabrication And Thermal Deformation Behavior Of In-situ(TiB+TiC)/Ti Composites

Due to the high specific modulus and specific strength,low density,good fatigue resistance and creep resistance,Titanium-based composite material has quickly become the topic of aerospace,medical and health and automobile manufacturing.However,the size and distribution of the reinforcement phase in the composite material and the interface combination of the reinforcement phase and the matrix will have a very important impact on the performance of the composite material.Therefore,in order to obtain a composite material with good comprehensive performance,it is particularly important to optimize the sintering process.In this article,the(TiC+TiB)/Tititanium composite material was prepared by spark plasma sintering.The effects of sintering temperature,ho lding time and sintering pressure on the microscopic morphology and mechanical properties of the composite were studied.By studying the rheological behavior at high temperature of(TiC+TiB)/Tititanium composite material,we can optimize its high-temperature processing technology,so as to provide a theoretical basis for the future processing and use of the material.The results show that:(1)As the sintering temperature increases from 950°C to1150°C,the compressive strength of the material presents a trend of first increasing and then decreasing.The maximum compressive strength is 2047 MPa at 1050°C.And it is also at 1050°C,the highest relative density is 99.3%.With the addition of the reinforcing phase,the mechanical properties of the material have been greatly improved.The compressive strength of the composite material with a volume fraction of the reinforcing phase of 10%is 1951 MPa,which is increased by 33.3%than that of pure titanium.The sintering pressure has the greatest influence on the relative density of the material.The relative density under a sintering pressure of 30MPa is only 98.6%.When the sintering pressure reaches 50 MPa,the relative density of the material reaches 99.7%.The holding time affects the progress of the reaction and the process of the material densification process.When the material is not insulated,the reaction process has not been completed yet,and the relative density at this time is only 91.8%.As the holding time increases to 5 min and 10 min,the relative density of the material reached to 98.6%and 99.2%,the composite material gradually completed the process of densification.(2)Using the thermophysical simulation method,the thermal deformation behavior of(TiC+TiB)/Tiwith a volume fraction of 5%of the reinforcement phase was studied.The constitutive equation of the peak stress of the(TiC+TiB)/Ticomposite and the processing map were constructed.Research found that the peak stress and flow stress of composite materials will decrease with the increase of sintering temperature and decrease of strain rate.The result of hot processing map shows that(TiC+TiB)/Ticomposite material is safe area to process is 1090-1120°C,0.004-0.001 s^-1.