(1. 南京理工大学 材料科学与工程系，南京 210094；
2. 中国兵器科学研究院 宁波分院 轻质材料研究所，宁波 315103)
摘 要: 对AZ31B/7075爆炸复合材料进行220 ℃以下低温退火。用Axiover 40 MAT型光学显微镜、Quanta200型扫描电镜、EDAX能谱仪及INSTRON 3367型力学性能试验机对复合界面结合区进行金相组织观察、成分线扫描以及剪切强度测试，研究复合界面结合区的低温退火演化机制。结果表明：随着加热温度的升高和保温时间的延长，在结合区镁合金发生回复、再结晶和晶粒长大，爆炸形成的绝热剪切带逐渐消失；原清晰的复合界面转变为具有一定厚度的由镁、铝互扩散形成的扩散层，扩散层组织结构由以固溶体为主逐渐转变为以金属间化合物为主，界面剪切断口由韧性断裂转变为脆性断裂；复合界面剪切强度取决于扩散层的组织结构，当扩散层组织以固溶体为主时，适当的加热可产生固溶强化而提高界面剪切强度，当扩散层组织以金属间化合物为主时，将降低界面剪切强度。
关键字: 铝合金/镁合金复合材料；AZ31B/7075复合材料；爆炸复合；界面演化；扩散层；绝热剪切带；剪切强度
alloy explosive composite plates after low temperature annealing
（1. Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
2. Lightweight Materials Institute, Ningbo Branch, China Academy of Ordnance Science, Ningbo 315103, China）
Abstract:The magnesium alloy (AZ31B)/aluminum alloy (Al7075) explosive composite plates were annealed at temperature below 220 ℃. The microstructure, elemental distribution and shear strength of the interface were studied with Axiover 40 MAT optical microscope, Quanta200 scanning electron microscope, EDAX energy dispersive spectrometer and INSTRON 3367 mechanical properties testing machine, respectively. The interface evolution due to low-temperature annealing was discussed. The results show that the recovery, recrystallization and grain growth of magnesium alloy at the binding region occur with increasing the heating temperature and prolonging the holding time, and the explosive adiabatic shear bands gradually disappear. The magnesium and aluminum inter-diffusion layers are formed instead of the original sharp composite interface, and the dominant components in the diffusion layer are gradually changed from solid solution into intermetallic compounds. At the same time, the characteristics of the interfacial shear fracture change from ductile to brittle fracture. The composite interfacial shear strength depends on the structure of the diffusion layer. When the structure of the diffusion layer is dominated by solid solution, the interfacial shear strength will be enhanced by proper heat treatment because of the solid solution strengthening. However, the interfacial shear strength is decreased by heating when the diffusion layer structure is dominated by intermetallic compounds.
Key words: Al/Mg composite; AZ31B/7075 composite explosive recombination; interface evolution; diffusion layer; adiabatic shear bands; shear strength
