Microstructure And Properties Of Cu/Ti₃SiC₂/C_f Composites

Carbon fiber possesses a series of outstanding properties,i.e.,high specific strength,high modulus,low density,high temperature resistance,corrosion resistance,antifatigue,creep resistance,electrical conductivity,thermal conductivity, low coefficient of thermal expansion and fine self-lubricating,antifriction.It becomes one of the most important reinforced-material.Carbon fiber reinforced copper matrix composite,with its excellent properties of high electrical conductivity, high thermal conductivity,self-lubricating,resisting electric-arc erosion and so on, is a promising functional composite.Ti3SiC2 is a novel layered ceramic material;it combines the merits of both the metals and ceramics.It has salient properties,such as low density,high melting point,nice electrical and thermal conductivity,high elastic modulus,high fracture toughness,oxidation resistance,thermal shock resistance and machinability.And more significantly,it has very low friction coefficient and nice self-lubricating properties.Ti₃SiC₂ is a promising ceramic reinforcement for copper.So the introduction of Ti₃SiC₂ to the copper matrix will exert the effect of dispersion strengthened copper,making the composites exhibit more excellent properties.This paper resolved the problem of wettability and uniform distribution among carbon fiber,Ti₃SiC₂ and copper matrix through electroplating and electrolessplating, combined the copper coated carbon fiber and Ti₃SiC₂ dispersion strengthened copper, prepared the Cu/Ti₃SiC₂/C_f composites.This material may integrate the excellent properties of carbon fiber,copper and Ti₃SiC₂.So it becomes to a novel copper matrix functional composite worthy of study.This paper studied composite's performance,especially the interface as a function of the sintering temperature.The research indicated that Cu reacted with Ti₃SiC₂ above 900℃with a result of the inter-diffusion of silicon and copper,and the relative amount of Cu and Ti₃SiC₂ is a dominant factor in affecting the reaction products.With a low content of Ti₃SiC₂ and the increase of sintering temperature, the Si from Ti₃SiC₂ diffused into the copper to form solid solution;The limited solubility of Si in Cu is only about 8at%,so when the content of Ti₃SiC₂ is above 50%,the excessive Si reacted with Cu to form inter-metallic compounds such as Cu₅Si,Cu₁₅S_i4,even(Cu,Si)η'with a complicated structure.With the process of the reaction,the content of Ti₃SiC₂ decreased and that of TiC increased.The results demonstrated that composites' density,relative density,hardness and electricity resistance increase with the increase of the sintefing temperature.The research indicated that the optimal sintering temperature is 800℃～850℃.At the temperature of 850℃,the Cu/Ti₃SiC₂ composites with different volume content of carbon fiber were fabricated,and the density,relative density,hardness,tensile strength,bending strength,compressive strength of the composites were researched as the function of carbon fiber's volume content.The results demonstrated that the density and relative density decrease,the electricity resistance increase with the increase of carbon fiber's content.The hardness reaches a maximum value of 130HBS with the 8vol%carbon fiber,and the tensile strength,bending strength and compressive strength reach their maximum values of 215MPa,421MPa and 623MPa with the 6vol%carbon fiber,then the values decrease.The microstructure of the composites was investigated by using SEM.And the strengthen mechanism and fracture mechanics of the composites were analyzed.