Effect Of Multiple Activation Substance On Mechanical Properties And Wear Properties Of Al₂O_3p/Steel Matrix Composites

With the development and progress of the iron and steel industry,serious overcapacity can no longer meet the needs of the mode rn industrial society.Instead,It has turned to the research of high hardness and wear-resistant ceramic particles reinforced steel matrix composites.Although Al ₂O₃ has good advantages in cheap price and excellent performance,the bond of the interface is weak because there have been a bad wettability of reinforcing particles.The addition of activated elements to the preforms improves the interfacial bonding of the composites.However,the single activation element may have an adverse effect on the matrix part.For example,when adding Ti to the preform,the Al ₂O₃ ceramic particles are coated with a Ti C interfacial layer with better wettability of the molten steel.The mechanical properties of the composites are obviously improved,while the C and Ti particles in the molten steel are reacted,and the hardness of the matrix is reduced.Therefore,it is necessary to study this problem by adding a variety of activating elements.In this paper,Al₂O_3p/high manganese steel composites were prepared by adding Ti particles and Si particles in the perform or adding Ti particles and changing the content of C in the matrix.We studied the effects of Microstructures by adding multiple activated substance elements.Through the test of hardness test,three-point bending and impact abrasive wear,the influences of multiple activating materials on mechanical properties and wear resistance of composites were investigated.After adding 20g Ti into the perform for preparing the Al ₂O_3p/high manganese steel composite,the depth of infiltration layer is about 3mm.The Rockwell hardness was37.2HRC.The microhardness of the matrix was 273.4 HV.The wear amount was0.143 cm³.With the increase of Ti content,the wear resistance and bending strength respectively grow to 0.686 cm³ and 432.1 MPa.But the infiltration depth and hardness all weaken.Al₂O_3p/high manganese steel composite material was prepared by squeeze casting.There was no crack in the matrix.A fter adding the Ti element,it was found that the Ti C coating layer was formed at the interface between the particles and the matrix.The interfacial bonding was good because of the good wettability between the Ti C and the steel liquid.When the Ti content is 10%of the ceramic particles,the macro hardness is 37.17HRC,the matrix microhardness is 273.4HV,and the bending strength is 320.4Mpa.The Al₂O_3p/steel matrix composites was added 15%Ti,10%Ti+3.5%Si and10%Ti+2.35%Si particles to the preform.In addition,it were prepared by adding10%Ti to the perform and making the 1.3wt%and 1.5wt%C content of the matrix.The hardness showed that the heat absorption of the preform to the molten steel was added with the increase of the amount of activated elements.Strong defects occur gradually in the matrix.When adding Si or C elements,the melting point of Ti can be reduced.The Ti particles will melt completely in the matrix,and the microhardness of the matrix will be improved.The results show that adding t he appropriate content of Si and C elements will cause a slight interfacial reaction.On the one hand,it reduces the melting point of Ti and reduces the absorption of Ti to the heat of the molten steel.On the other hand,the interface products promote th e interfacial bonding and improve the mechanical properties.The macro hardness of the composite with 10%Ti and 3.5%Si is36.17HRC,and the microhardness of the matrix is 296HV.When adding 2.35%Si,the Ti particles are not completely melted,which reduces the solid solution strengthening effect.It makes the hardness decrease.The macro hardness is35.84HRC,and the matrix microhardness is 259HV.When 10%Ti is added and the content of matrix C is 1.3wt%,C and Ti react to Ti C.The microhardness of the matrix is increased by 0.58%and the macro hardness is 36.57HRC.When C content is 1.5wt%,there are a lot of brittle carbides in the matrix.The macro hardness and the matrix microhardness respectively decrease by 2.77%and 3.91%.After adding two activating elements,the plasticity and toughness of Al ₂O_3p/steel composites were higher than those of 10%Ti composites.With the increase of silicon element,the plasticity and toughness of the matrix increase,but the bending strength decreases.When the carbon co ntent increased,the matrix strain increased and the bending strength decreased by 90.4%and 52.4%respectively.When two kinds of active elements are added,the wear resistance of the composites with Si elements is better than that of the composite with 10%Ti.The wear resistance of composite materials with Ti and C get worse.