双屏蔽(B4C-W)/6061Al层状复合板设计与性能

基于B₄C和W良好的屏蔽中子和γ射线性能，采用6061铝合金作为基体，设计了一种新型双屏蔽(B₄C-W)/6061Al层状复合材料，通过放电等离子烧结后加热轧制成板材，对制备的复合材料微观组织和力学性能进行了研究。结果表明，屏蔽组元B₄C和W颗粒均匀地分布在6061Al基体中，层界面、B₄C/Al、W/Al异质界面之间结合良好，无空隙和裂纹。在颗粒与基体界面处形成扩散层，扩散层的厚度约为6 μm (W/Al)和4 μm (W/Al)。轧制态的(B₄C-W)/6061Al层状复合板的屈服强度(109 MPa)和极限抗拉强度(245 MPa)明显优于烧结态的复合材料，但断裂韧性降低。强度提高的原因主要是轧制后颗粒的二次分布、均匀性及界面结合强度提高，基体合金的晶粒尺寸减小，位错密度增加。层状复合板的断裂方式为基体合金的韧性断裂和颗粒的脆性断裂。 

Design and properties of double shielding (B4C-W)/6061Al laminated composite board

Based on the good shielding performance of B₄C and W against neutrons and gamma rays, a new type of double shielding (B₄C-W)/6061Al laminated composite was designed by using 6061 aluminum alloy as matrix. The composite was prepared by spark plasma sintering and then heated and rolled into a plate. The microstructure and mechanical properties of the prepared composite were studied. The results show that the shielding component B₄C and W particles are uniformly distributed in the 6061Al matrix, and the interlayer interface, B₄C/Al, and W/Al heterogeneous interface are well bonded without voids and cracks. The diffusion layers are formed at the interface between the particles and the matrix, and the thickness of the diffusion layers are about 6 μm (W/Al) and 4 μm (W/Al). The yield strength (109 MPa) and ultimate tensile strength (245 MPa) of the rolled (B₄C-W)/6061Al laminated composite are significantly better than those of the sintered (B₄C-W)/6061Al laminated composite, but the fracture toughness is reduced. The main reasons for the increase of strength are the secondary distribution and uniformity of particles and the interface bonding strength is increased after rolling, and the grain size of the matrix alloy decreases and the dislocation density increases. The fracture modes of the composite are ductile fracture of matrix alloy and brittle fracture of the particles.