Preparation And Properties Of Ti₂SnC Reinforced Copper Matrix Composites

Copper matrix composites are widely used in the lead frame of integrated circuit,pantograph,brush and contact material of electric locomotive due to their excellent conductivity,thermal conductivity,high strength and high temperature resistance.Generally speaking,the addition of reinforcing phase can improve some mechanical properties,but reduce its conductivity,so it is necessary to select reinforcing phase with good conductivity.Ti₂SnC is a kind of ternary layered conductive ceramics,which has good conductivity,high modulus of elasticity,self-lubricating property,chemical corrosion resistance and processability.It is an ideal reinforcing phase of copper matrix composite.In this experiment,the Ti₂SnC/Cu composite with high purity was prepared by liquid-solid reaction method,and then the Ti₂SnC/Cu composite was prepared by direct thermal powder sintering technology.The effects of particle size,addition amount,sintering temperature,pressing pressure,holding time and other parameters on the density,hardness,conductivity,tensile strength,elongation and other properties of Ti₂SnC/Cu composite were studied.In order to determine the best preparation process parameters of Ti₂SnC/Cu composite,the orthogonal test of four factors and three levels was carried out,and the range analysis was carried out.The conductivity and tensile strength of the composite were taken as indicators.It was found that the main factors affecting the conductivity were:particle size>holding time>adding amount>forming pressure.The parameters to obtain the best conductivity were particle size 2?m,holding time 30 min,adding content 8wt%,pressure 45MPa;factors affecting the tensile strength:addition amount>particle size>holding time>pressure.The parameters to obtain the best tensile strength are the addition content of 8wt%,particle size of 2?m,holding time of 60min,pressure45MPa.In order to further explore the influence of various factors on the properties of composite materials,a single factor test was carried out.When the mass fraction of Ti₂SnC is 5%,the comprehensive properties are the best,the density and conductivity are 94%and 39%IACS respectively,the tensile strength is 248MPa,and the hardness is 88.7HBS.It was found that when the holding time was 60 min,the highest conductivity of the composite was 30%IACS,while the impact toughness and Brinell hardness showed the opposite trend.When the particle size of Ti₂SnC is 10?m,the highest conductivity is 37%IACS.When the pressure is 55MPa,the conductivity reaches 44.7%IACS,and the density is 94.9%.Therefore,with the increase of the pressure,the conductivity increases.To further optimize the microstructure and mechanical properties of composite materials,the conductivity and the tensile properties of the optimal sample 5,sample9,sample 16 and sample 18 to do rolling experiment.The test limits of 5 and 9 samples of rolling reduction are 40%,the conductivity of the sample 5 after rolling increased to 40%IACS from 32.8%IACS,increased by 25.5%.Density increased from 93.8%to96.8%;The conductivity of sample no.9 after rolling was 48.2%IACS,which increased 7.8%in density from 94.9%to 98.8%.The conductivity also increased from44.7%IACS before rolling to 48.2%IACS.