Preparation And Properties Of SiC?TiC Particles Reinforced Aluminum Matrix Composites By HIP And SPS

In this paper,the SiC/2024Al matrix composites and TiC/Al matrix composites are prepared by thermal isostatic pressure and discharge plasma sintering.In this paper,the density,hardness,tensile properties,compression properties,microstructure and morphology of the composites are studied,and the simulated braking test is carried out.The friction and wear characteristics of the composites are analyzed and studied,and the influence of heat treatment process and particle size on physical mechanical properties and wear properties of composite materials are also analyzed.At the same time,the wear morphology and wear law of the composite was analyzed,and the wear mechanism of the particle reinforced aluminum matrix composites under the test conditions was discussed.The results of this study show that:In SiC/2024Al composites prepared by HIP,SiC particles are well combined with 2024 aluminum matrix.There was no obvious change before and after heat treatment.After heat treatment,the Al2Cu phase disappeared and A12MgCu phase(S' phase)appeared.SiC/2024 Al matrix composites have small density,high hardness and high strength.After heat treatment,the density of the composites has no obvious change,the hardness is increased by 50%,the tensile strength and the prescribed plastic extension strength are increased by 44%and 88%respectively,and the toughness is slightly reduced.The wear performance of SiC/2024Al matrix composites is stable.After heat treatment,the wear rate of the composites decreases significantly,and the wear resistance is improved significantly.After heat treatment,the friction coefficient of composites decreased slightly,but the stability of friction properties increased.The distribution of TiC particles with the matrix in the TiC/Al matrix composites with different volume ratios prospered by SPS is good,The TiC particles distribution at the boundary of aluminum based particles.The large TiC particles have no obvious agglomeration,and some small TiC particles are gathered around the large TiC particles.There are Al4C3 phase and TiAl phase in the composites with small high particle size proportion.The hardness of TiC/Al matrix composites is obviously higher than that of matrix.With the increase of large TiC particle ratio,the density of composites decreases,but the hardness and compressive strength of composites increase.The wear performance of TiC/Al matrix composites prospered by SPS is stable.The wear rate decreases with the increase of the volume ratio of the large TiC particles in the reinforced phase,but the decrease of the wear rate of the composite is smaller after the addition of the large particle TiC is more than 20%.With the increase of the volume ratio of large TiC particles,the friction coefficient of composites decreases first and then increases.The fluctuation of friction coefficient increases.After heat treatment,the wear surface of SiC/2024Al matrix composites has a lot of deep furrow scratches.After heat treatment,because of the supporting effect of the reinforced particles on the composite is increased.The depth and width of the scratches in the furrow are smaller,and the number is less,and oxides appear on the worn surface,the wear resistance of the composites is improved.The friction mechanism is serious abrasive wear and adhesive wear before heat treatment.After heat treatment,the friction and wear mechanisms are changed to slight delamination wear and oxidation wear.With the increase of the size ratio of large particle size TiC particles in the reinforced phase of the reinforced aluminum matrix composite with double grain size TiC particles,the enhanced phase enhancement of large particle size is dominant,the scratches gradually become shallow and the number gradually decreases,and the cracks and spalling pits on the wear surface also decrease,and the abrasive grains of the wear machine are serious.Wear and adhesive wear turn to minor abrasive wear and wear resistance.