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通过力学拉伸、DSC热分析和透射电镜观察,研究了150℃不同时间热暴露对2524合金组织与性能的影响。结果表明:经自然时效(T351)和高温短时人工时效处理(170℃×30min)的合金在热暴露过程中,合金强度随热暴露时间的延长先增加后下降,而伸长率逐渐下降。热暴露500h后,高温短时人工时效处理的试样力学性能退化较快。2524合金高温短时人工时效获得的较大尺寸的原子偏聚(GPB)区比自然时效中的GPB区较难回溶,因此形成的S′相尺寸较大,更易粗化。150℃热暴露合金力学性能衰退的主要原因可归结为合金基体主要强化相S′(Al2CuMg)相粗化以及晶界无析出带(PFZ)的宽化。
The effects of heat exposure at 150 ℃ on the microstructure and properties of 2524 alloy were studied by mechanical tensile test, DSC thermal analysis and transmission electron microscopy. The results show that the alloy strength increases first and then decreases with the increase of heat exposure time, while the elongation decreases gradually with the exposure time of T351 and 170 ℃ × 30min. After 500h thermal exposure, the mechanical properties of samples treated with high temperature and short-term artificial aging degenerated rapidly. The larger size of the atomic segregation (GPB) region obtained by 2524 alloy at high temperature and short-term artificial aging is more difficult to dissolve than the natural aging GPB region, resulting in a larger size and coarsening of the S ’phase. The main reason of mechanical properties degradation of 150 ℃ hot-exposed alloy can be attributed to the coarsening of Al2CuMg phase and the broadening of PFZ.