Investigation On Spark Plasma Sintering Process Of Laminated Aluminum Matrix Composites

Laminated aluminum matrix composites have a layered structure that can be designed.The composite materials with specific properties can be prepared by combining component materials according to different layer spacings,layer thickness ratios,and number of layers.At the same time,aluminum-based laminated composites have the characteristics of low preparation cost,low density,high specific strength,and good fracture toughness.They are widely used in the aerospace and military fields.There are many preparation methods of aluminum based laminated composites,among which hot pressing sintering is a common one.Compared with hot pressing sintering,spark plasma sintering(SPS)has the characteristics of low sintering temperature and fast sintering,but it is less studied in the preparation of aluminum based laminated composites.In this paper,pure aluminum foil and B4C powder are selected as raw materials,and accumulative fold-forging(AFF)and spark plasma sintering technology are used to prepare pure aluminum lamination and B4C/Al lamination composites.The effects of different sintering processes,such as sintering temperature,sintering pressure and holding time,on the micro-structure and mechanical properties of the laminated composites are focused.Through the comparison and analysis of the experimental results,the optimal spark plasma sintering process is obtained.The main research contents and conclusions are as follows:(1)It is found that as the sintering temperature and sintering pressure increase,the layer thickness of the laminated composites material decreases,the density increases,and the hardness and compressive performance improve.As the holding time increases,the layer thickness of the laminated composites material decreases,and the density increases,but its hardness and compressive properties tend to increase first and then decrease.(2)The optimal sintering process for pure aluminum laminated materials is a sintering temperature of 500?,a sintering pressure of 50MPa,and a holding time of 30minutes.At this time,the density,lateral hardness,surface hardness,compressive strength of compression perpendicular to the layer direction,and compressive strength of compression parallel to the layer direction were 2.693g/cm3,65.0HV,78.4HV,138MPa,and 121MPa.(3)The properties of B4C/Al laminated composites materials are better when the sintering temperature is 500?,the sintering pressure is 50MPa and the holding time is 30min.At this time,the density,side hardness,surface hardness,compressive strength of load perpendicular to layer loading and compressive strength of load parallel to layer loading are 2.680g/cm3,116.6HV,125.4HV,238MPa and 185MPa.(4)Due to the addition of ceramic reinforcement phase,under the same conditions,compared with pure aluminum,B4C/Al laminated material has smaller thickness reduction and lower density,but its hardness increases about 50HV,and its compressive strength increases at least 60MPa.The research work in this paper shows that the spark plasma sintering technology can be applied to the preparation of laminated aluminum matrix composites,and the optimal sintering process is given,which lays the foundation for future research work.