Abstract

Multilayered Al/Ni energetic structural materials integrating exothermic properties and mechanical properties were prepared by the method of electrodeposition and hot pressing in this research. Then, the uniaxial quasi-static compression and split Hopkinson pressure bar experiments were conducted at strain rates from 10⁻⁴ to 6.5 × 10³ s⁻¹ at room temperature. The effects of compression strain rate on the microstructure evolution and the compressive properties of multilayered Al/Ni energetic structural materials were systematically investigated. With increasing quasi-static compression strain rate, the compression strength increased slightly for two kinds of Al/Ni multilayers prepared under different hot pressing time. With the hot pressing process extending to 4 h, the dynamic compression strength of multilayered Al/Ni composites monotonically increased from 494.7 to 564.2 MPa with increasing strain rate. It was shown that Al/Ni energetic structural materials exhibited evident strain hardening and strain rate strengthening. However, when the compression strain rate reached 6500 s⁻¹, the Al/Ni composite prepared with the hot pressing time of 1 h showed prominent thermal softening. Notwithstanding, it was found that the compression strength of Al/Ni composite prepared at 4 h was evidently higher than that at 1 h, since the second phase reinforcement counteracted the thermal softening. In addition, the critical failure strain presented obviously increasing tendency with the increased compression strain rates.

中文翻译：

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不同应变速率下多层Al / Ni高能结构材料的组织演变和压缩性能

摘要

本研究采用电沉积和热压的方法制备了兼具放热性能和力学性能的多层Al / Ni高能结构材料。然后，在10 ^-4到6.5×10 ³  s ^-1的应变速率下进行了单轴准静态压缩和霍普金森分裂压力棒实验。在室温下。系统研究了压缩应变速率对多层Al / Ni高能结构材料微观组织演变和压缩性能的影响。随着准静态压缩应变率的增加，在不同热压时间下制备的两种Al / Ni多层膜的压缩强度略有提高。随着热压过程延长至4 h，多层Al / Ni复合材料的动态压缩强度随着应变速率的增加而从494.7 MPa单调增加到564.2 MPa。结果表明，Al / Ni高能结构材料表现出明显的应变硬化和应变速率增强。但是，当压缩应变率达到6500 s ^-1时，以1h的热压时间制备的Al / Ni复合材料表现出明显的热软化。尽管如此，发现由于第二相增强抵消了热软化，在4h制备的Al / Ni复合材料的压缩强度明显高于在1h的压缩强度。此外，随着压缩应变率的增加，临界破坏应变也呈现出明显的增加趋势。