| With the rapid development of nuclear power in the recent 30 years,there will be greater than tons of nuclear waste for safe disposal and proper planning.Al-B4C composites have the properties of thermal neutron absorption and good mechanical properties,which can be used as the structure and function materials,and it is an economical and safe storage rack for spent fuel.In this paper,neutron absorption material Al-B4C composites used as the fuel wet storage of the spent fuel in the nuclear power system needed to be improved.Double-particle hybrid reinforced composite with high-density tungsten carbide and B4C was designed.The performance of the neutron-gamma ray shielding is exceptional in the practical application of the environment.The tungsten element of the composite material is propitious to not only slow fast neutron,but improve the shielding of one and two times of y.Optimization of preparation makes boron carbide(B4C)particles and tungsten carbide(WC)particles uniformly distributed in the aluminum alloy.The composites prepared by vacuum hot pressing exhibit superior performance and wear to adapt to the harsh working environment.In terms of functional and structural material integration and comprehensive nuclear shielding protection,this material is an important significance.In this paper,2009 Al alloy matrix composites reinforced with different volume fraction of boron carbide(20%and 25%)and with different volume fraction of tungsten carbide(5%,10%and 15%)were prepared by vacuum hot pressing method.Preparation and morphology of the composite were investigated.The preparation process of the(25vol.%B4C+10vol.%WC)p/Al composite was mainly optimized.and by X-ray diffraction analysis,metallographic microscope,scanning electron microscope(SEM),transmission electron microscopy(TEM),microstructure evolution of the composites,the effect of particles content and heat treatment on the mechanical properties of the composite were studied,main research results show that:(1)High volume fraction(B4C+WC)hybrid reinforced aluminum matrix composites were prepared by vacuum hot pressing method.Density of composites was>96%.Distribution of B4C and WC particles in the composites was basically uniform.(2)In the preparation process,WC particles are easy to break,which makes the composite material B4C and WC particles disperse evenly.B4C and WC premixed 2h,then mixture with matrix powders,not only reduced the mixing time,but also obtained uniform particle distribution.Vacuum preparation process of the(25%B4C+10%WC)p/Al composite was studied.The results showed that the optimal process of vacuum hot pressing is vacuum hot pressing temperature 620?,the sintering time is 80 min.The best heat treatment was 500?C 6h,495? water quenching.The aging temperature was 175?.There is a significant interfacial reaction between WC and Al.While the reaction products of A1 and B4C are slight,and the reaction products are not located at the interface of the particles.With the increase of the temperature,the interface between WC particles and matr:ix is serrated.Main interface products:Al3BC and W2B5.(3)The hardness of the 4 kinds of composites increased with the aging time,and the hardness of the composites was the maximum when aging time was 10-12h..With the increase of WC particles,the hardness of the composite increased obviously,but the aging ability decreased.The maximum aging hardness of(20%B4C+15%WC)p/2009Al was 314.6HV.However,the peak aging platform is not obvious,when(20%B4C+15%WC)p/2009AIAl composites aging 10h.Age hardening ability is lower than 30HV.(4)the maximum compressive strength in four kinds of composite materials before and after aging was the one of(20%B4C+15%WC)p/2009Al composites,The compressive strength of(20%B4C+15%WC)p/2009Al composites before and after aging are 749.9 MPa and 831.4 MPa,respectively.While the plasticity of(20%B4C+15%WC)p/2009A1 composites is the worst,and the total compression strain before and after aging is 0.0756 and 0.0848,respectively. |
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