High specific strength and radiation shielding of laminated AA2024/RO5252 and AA2024/AA1060/RO5252 composite materials prepared by differential temperature rolling

The shielding efficiency, mechanical property, interfacial bonding strength and microstructure of the laminated AA2024/RO5252 and AA2024/AA1060/RO5252 composites produced by differential temperature rolling, followed by solution treatment at 500°C for 1.5h and aging at 200°C for 8h, were investigated by total dose radiation tests, tensile tests, shear tests, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) techniques. Both composites showed excellent radiation shielding effect, which were ~60% higher than that of single AA2024 plate that had almost the same surface density. The tensile test and shear test results showed that the yield strength, tensile strength, elongation and interfacial bonding strength of two-layer and three-layer composites in the aged state were 364±1MPa, 476±1MPa, 14±2%, 84±1MPa and 353±1MPa, 451±1MPa, 11±1%, 54±1MPa, respectively. The SEM observations of the shear fracture surface demonstrated a clear increase in the residual aluminum area on the RO5252 side after heat treatment in the two composites. The EBSD results for the cross section of interface showed that after rolling, the RO5252 layer was deformed, while the AA2024 layer was in a state between recovery and recrystallization. After heat treatment, the RO5252 layer remained deformed, while the AA2024 layer underwent a complete recrystallization process. The SEM and TEM observations showed separate Al3339.8Cu231.95Ta2336 intermetallic compound particles at the interface of two-layer composites. But for the three-layer composites, no intermetallic compounds were observed, which is beneficial for improving the property of thermal cycling. These results provide important information for developing laminated Al /Ta based alloy composite material.

本研究针对经差温轧制（differential temperature rolling）制备，随后进行500℃固溶处理1.5h、200℃时效处理8h的AA2024/RO5252与AA2024/AA1060/RO5252层状复合材料，采用总剂量辐射试验、拉伸试验、剪切试验、扫描电子显微镜（scanning electron microscopy, SEM）、电子背散射衍射（electron backscatter diffraction, EBSD）以及透射电子显微镜（transmission electron microscopy, TEM）等测试与表征技术，对其辐射屏蔽效能、力学性能、界面结合强度与微观组织展开了系统探究。两种复合材料均展现出优异的辐射屏蔽效果，其屏蔽效能较表面密度近乎一致的单层AA2024板材提升约60%。拉伸与剪切试验结果表明，时效态两层复合材料与三层复合材料的屈服强度、抗拉强度、断后伸长率及界面结合强度分别为364±1MPa、476±1MPa、14±2%、84±1MPa，以及353±1MPa、451±1MPa、11±1%、54±1MPa。对剪切断口的扫描电子显微镜观察显示，热处理后两种复合材料的RO5252侧残余铝区域均显著增加。界面截面的电子背散射衍射结果显示：轧制阶段RO5252层发生塑性变形，AA2024层处于回复与再结晶之间的过渡状态；经热处理后，RO5252层仍维持变形状态，而AA2024层则完成了完全再结晶过程。扫描电子显微镜与透射电子显微镜观察发现，两层复合材料的界面处存在离散分布的Al3339.8Cu231.95Ta2336金属间化合物（intermetallic compound）颗粒；而三层复合材料的界面未观察到金属间化合物，该特征有利于提升其热循环性能。上述研究结果为开发层状铝基/钽基合金复合材料提供了重要的参考依据。