| TiC is a reinforcement with a high usage rate in particle-reinforced aluminum-based composite materials,but the poor wettability between TiC particles and aluminum matrix makes it difficult to prepare composite materials with uniform structure and excellent performance.Compared to TiC with a 1:1 stoichiometric ratio,the non-stoichiometric TiCx(x<1)has good wettability with the metal matrix,at the same time it has the basic characteristics of normal stoichiometric TiC particles,which is an ideal Metal matrix composite reinforcement.However,the traditional method cannot fully mix Ti and C elements in the all mill,and TiC with a Ti/C atomic ratio of 1:1 has a lower Gibbs free energy,which will cause a large amount of The TiC(Ti:C=1:1)phase is formed.In this paper,a new ternary layered compound Ti2AlC and Cu are used as raw materials to prepare the TiCx/Cu(Al)intermediate by in-situ reaction,and then the intermediate remelting and dilution method is used to prepare the non-metering ratio TiCx as the reinforcing phase,Al-4.5 Aluminum matrix composites with Cu deformed aluminum alloy and Al-10Cu cast aluminum alloy as matrix,and using DSC,XRD,TEM and other testing techniques to characterize the structure and mechanical properties of aluminum matrix composites.The main results of the article are as follows:(1)Ti2AlC and Cu can react in situ for a certain period of time at a temperature above 900? to form the TiCx phase.With the increase of the sintering temperature and the extension of the holding time,the value of x in TiCx is gradually increasing.Under the sintering process of 1000? and 60 min heat preservation,only the diffraction peaks of TiCx and Cu(Al)exist in the intermediate XRD results.(2)Adopt TiCx/Cu(Al)intermediate remelting and diluting process to introduce non-metering ratio TiCx to Al-10Cu casting alloy,whose main phases are ?-Al,Al2Cu,TiCx and Al3Ti phase,and the values of x in TiCx are all less than 0.7.High-resolution transmission electron microscopy analysis shows that the size of TiCx reaches nanometers,which is mainly distributed in the crystal and has a good interface with the aluminum substrate.When the amount of TiCx added is 0.5 wt.%,the hardness value of the as-cast composite is the largest,about 134.7 HV and the addition of TiCx improves the high-temperature mechanical properties of Al-10Cu-based composites.(3)Al-4.5Cu-based composite materials with different TiCx content were prepared by remelting and dilution,and the aging streng thening effect and deforma bility of the composite materials were evaluated.The phase composition of the composite material is ?-Al,TiCx,A12Cu and Al3Ti phases.As the TiCx content increases,the grains of the composite material are refined,and the hardness of the aged composite increases.When the TiCx content is 0.5 wt.%,the grain size is about 10?28 ?m,and the maximum hardness value is 114.6 HV.The thermal activation energy of 0.5 wt.%TiCx/Al-4.5Cu matrix composite material is 186.15kJ/mol,and the constitutive equation between flow stress,deformation temperature and strain rate is:?=1.85x1014[sinh(0.01847?)]5.24904exp(-186.15×103/8.314T)(4)The addition of element boron significantly improves the structure and properties of TiCx/Al-10Cu composites prepared by intermediate remelting and dilution.XRD results show that Ti2AlC particles react with Cu under the sintering process at 1000? for 60 minutes.The in-situ reaction between the two is affected by the addition of a small amount of boron element.The objects are TiCx,TiB2 and Cu(Al)phases.With the increase of the boron element content,the x value of the non-metering TiCx phase in the composite material gradually decreases.When the amount of boron added is 0.35 wt.%,the Vickers hardness value of the TiCx/Al-10Cu matrix composite is the largest,which is 151.0 HV.Co MPared with Al-lOCu alloy,the increase is 20.1%.In addition,the addition of boron element improves the high temperature performance of the composite material. |
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