高含钨铝基屏蔽材料的热变形致密化制备及组织性能研究

    Microstructure and Properties of Aluminum Based Shielding Materials with High Tungsten Concentration by Hot Deformation Densification Technology

    • 摘要: 钨硼铝复合材料作为一种新型综合屏蔽材料,在核辐射防护领域展现出良好前景。然而,高钨含量条件下复合材料的致密化制备是高性能钨硼铝材料开发面临的关键瓶颈。采用镜框约束锻造、轧制相结合的热变形致密化工艺制备钨硼铝复合板材,研究了材料经锻造、轧制后的组织性能变化,分析了轧制变形量对材料致密度的影响,测试得到了该板材的综合屏蔽性能。结果表明:坯料经约束锻造后,复合坯边部与铝框紧密结合,坯料致密度得到显著提高,有利于后续轧制工艺的顺利开展;而针对锻坯的热轧过程,通过多道次、大变形量轧制,能够有效解决高含量增强体颗粒引起的加工开裂难题,实现钨硼铝板材的致密化制备。所制材料同时展现出优异的力学性能和综合屏蔽性能。板材的室温抗拉强度可达到290 MPa以上;材料的热中子屏蔽率可达98%以上(厚10 mm),对60Co和137Cs源γ射线的线性衰减系数分别为0.52 cm-1和0.91 cm-1

       

      Abstract: As a novel kind of combined shielding materials, tungsten-boron-aluminum composite has shown a good prospect in the field of nuclear radiation protection. However, the densification of the composites with high tungsten concentration is still a key bottleneck in developing high-performance tungsten-boron-aluminum materials. Through a hot deformation densification process combining frame constraint forging and rolling, tungsten-boron-aluminum composite sheets were prepared. The microstructures and properties of the materials after forging and rolling were studied, and the influence of rolling deformation on the density of the materials was analyzed. The combined shielding performance of the sheets was obtained. The results show that the edge of the composite is combined tightly with the aluminum frame and the density of the materials is greatly increased after the constrained forging process, which would benefit the subsequent rolling of the materials. For the hot rolling of the forging blanks, a rolling process with multiple passes and large deformation would effectively solve the cracking problems of the composites with high content reinforcements, resulting in successful preparation of high density tungsten-boron-aluminum materials. The as-prepared materials exhibit both high mechanical properties and comprehensive shielding performance. The tensile strength of the composite could reach 290 MPa at room temperature. The thermal neutron shielding rate could reach above 98%(10 mm thickness) and the linear attenuation coefficients are 0.52 cm-1 and 0.91 cm-1 respectively for γ-rays from 60Co and 137Cs sources.

       

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