Preparation And Property Study Of Al/RSiC Composites With Three Dimensional Interpenetrating Network Structure

Because each phase can be retained,composites with three-dimensional interpenetrating network structure can realize the effective control of the composites of structure and function.So we choose Recrystallized silicon carbide(RSi C) as substrate,which has high strength,high hardness, good wear resistance,high thermal conductivity(TC),low thermal expansion coefficient(CTEs);meanwhile,choose ZL102 Al alloy as the second phase,which has good wettability between Si C and ZL102 Al alloy,then,3D-Al/RSi C composites were prepared by the method of the vacuum air pressure melt infiltration.This kind of composite has combinated the excellent properties of RSi C and ZL102 Al alloy,and shows a wide application prospect in electronic packaging,aerospace,automotive,machinery manufacturing and other industrial areast.In this paper,effects of the RSi C substrate density on the mechanical properties, thermal expansion coefficient(CTEs),thermal conductivity(TC),and the volume resistivity was studied, and effects of the RSi C substrate density on microstructure, mechanical properties,thermal expansion coefficient,thermal conductivity and volume resistivity of 3D-Al/RSi C composite,and the related theory discussion has also been carried on.The main conclusions are as follows:(1) Flexural strength at room temperature and TC of RSi C ceramic substrates decrease with increasing of the porosity;volume resistivity of the RSi C ceramic increases with increasing of porosity;porosity has little impact on CTEs of RSi C, but CTEs increases along with the rise of temperature.(2) Al/RSi C composites with double continuous three-dimensional interpenetrating network structure with relative density higher than 98% were successfully prepared by the method of the vacuum air pressure melt infiltration;along with the increasing of volume fraction of Si C, the room-temperature bending strength of the composites increase firstly and then decrease, the bending strength of the composite is 181 Mpa when the volume fraction of Si C is 72%, increasing nearly three times more than substrate;the volume resistivity of composites increase with the increasing of the volume fraction of Si C, have a significantly lower than the substrate,about 4 orders of magnitude.(3) The measured value of the CTEs and calculated value of the CTEs according to Turner formula and Rule of Mixtures were comparative analyzed, calculated values of the CTEs according to Turner formula is more close to the measured values;rigid structure of RSi C has important effects on CTEs of composites, RSi C can effectively bind the plastic deformation and high temperature softening of aluminum alloy in the expansion process,the CTEs of composites(4.31~4.65) ×10-6/? is far lower than the CTEs of Al alloy18.4 ×10-6/?, and decreases with the increasing the volume fraction of Si C.(4) There are two kinds of mechanism of thermal conductivity in 3D-Al/RSi C composites,namely the phonon thermal conductance of RSi C and the free electron heat transfer of Al alloy,When the volume fraction of Si C increases from 66% to 83%, the TC of the composite down from 260W·m-1·K-1 to 234W·m-1·K-1.