(北京有色金属研究总院 有色金属材料制备加工国家重点实验室，
北京 100088)
摘 要: 研究了7B04合金单级时效处理过程中时效温度和时效时间对合金力学性能和电导率的影响， 观察和对比了几种不同时效处理制度下合金的显微组织。 结果表明： 单级时效处理的温度越高， 合金达到峰时效所需的时间越短， 材料的峰时效强度和延伸率越低。 电导率随时效时间的延长而不断上升； 时效温度越高， 电导率的增长速率越快。 峰时效合金基体内有大量细小的弥散相析出， 晶界析出相呈连续分布。 当时效温度较低时， 过时效合金的显微组织与峰时效没有明显差别； 当时效温度较高时， 过时效合金内粗大析出相的数量明显增加， 晶界析出相呈不连续分布。 不同时效温度下的峰时效和过时效合金中均不存在明显的晶间无析出带。
关键字: 7B04合金； 预拉伸厚板； 单级时效； 微观组织； 力学性能
（ State Key Laboratory for Fabrication and Processing of Nonferrous Metals, General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract: The effect of one-step ageing temperature and time upon mechanical properties and electrical conductivity of 7B04 pre-stretched thick plate was studied， and the microstructures of the alloy aged at different temperatures were compared. The results show that the higher the ageing temperature is, the shorter the peak ageing time is. The strength and elongation of the peak-aged alloy will be lowered when the ageing temperature is higher. With increasing the ageing time, the electrical conductivity becomes large. The higher the ageing temperature is, the faster the speed rate of electrical conductivity grows. The microstructure of matrix in peak-aged alloy consists of fine dispersed precipitates and precipitates from grain are continuous. When the ageing temperature is lower than 120 ℃, there are no obvious microstructure difference between peak-aged and over-aged alloys; When the ageing temperature is higher than 125 ℃, there are many coarse precipitates in over-aged alloys and the precipitates from grain are discontinuous. There are no obvious precipitate free zones along the grain boundary in both peak-aged and over-aged alloys under different ageing temperatures.
Key words: 7B04 alloy; pre-stretched thick plate; one-step ageing; microstructure; mechanical property
