Preparation And Properties Of High Volume Fraction Of W/al Composites By Pressure Infiltration Method

With the continuous development of nuclear power industry,the energy problem has been greatly alleviated.As a clean and efficient energy source,nuclear energy has its undoubted advantages,but it also brings radiation-related problems.The most penetrating rays in gamma rays are neutron and gamma rays.This paper aims to prepare an anti-radiation structural material,so that the linear shielding coefficient of gamma rays meets certain requirements and has neutron shielding performance.The shielding property of the composite material for rays is basically proportional to the volume fraction of the shielding particles,while the composite material with high volume fraction will correspondingly lead to the decline of mechanical properties and corrosion properties.In this paper,by the high linear shielding coefficient W and WC to strengthen,with low density of pure Al and Al2024 as matrix,using ball mill by blending with pressure impregnation method of preparation of high body containing tungsten aluminum matrix composites,using advanced analysis methods on the microstructure of the composite,phase distribution,mechanical properties,corrosion resistance,and shielding performance system research,analyzes the related influencing factors;Five kinds of high-volume w-al matrix composites were prepared.The speed of ball grinding is 150rpm and the ball grinding time is 2 h.For the pressure infiltration process,the prefabricated block pressure is 40kN,the insulation time is 1.5h,and the composite material containing W powder is insulated for 0.5h.Under SEM,the material was uniformly distributed,and the shielded particles were uniformly distributed in the Al matrix,without obvious holes or especially obvious particle dilution zone.The products of interface reaction of composite materials are WAl₄,WAl₁₂and WAl₅.The interface reaction changes the shape of shielded particles from polyhedron to sphere,and the particle size decreases.The particle size changes of W are larger than that of WC,and Cu,Mg and other elements in 2024Al matrix tend to converge towards the interface.With the increase of the volume fraction of W and the decrease of the volume fraction of WC in the composite material,the quantitative calculation result of the distribution uniformity of shielded particles gradually decreases,but the extreme value difference is less than 10%.Bending strength continues to decline,which is because the increase in the volume fraction of W will lead to increasingly serious interfacial reactions and the formation of brittle intermetallic compounds.The fracture of 25W10WC/Al composite material is characterized by some ductile fracture.Corrosion resistance has also been improved.The observation of corrosion morphology shows that there are many pitting corrosion in the interface between WC and Al matrix,and the corrosion of 2024Al is more serious,forming a corrosion pit.The linear shielding coefficient of the composite material increases gradually,and the measured shielding coefficient is a little smaller than the theoretical calculation value.The interface reaction makes part of W disperse in the matrix,which improves the dispersion of tungsten element and thus improves the shielding performance.Therefore,the gap between the theoretical calculation value and the measured value of W is smaller.