机构地区： 中南大学材料科学与工程学院
出 处： 《中南大学学报（自然科学版）》 2009年第4期921-925,共5页
摘 要： 采用室温拉伸性能测试、金相和透射电子显微分析方法研究热暴露温度和时间对30mm厚2124-T851铝合金板材组织与力学性能的影响。研究结果表明:在高于板材190℃最终时效温度下热暴露,合金强度下降而伸长率上升,温度愈高、时间愈长,强度下降和伸长率上升就愈快,于250℃热暴露50h和100h时,屈服强度分别降低53%和58%,伸长率分别上升约23%和55%;低于最终时效温度热暴露,若热暴露温度在150℃以下,则合金拉伸力学性能变化不大;当热暴露温度接近最终时效温度,如175℃时,若热暴露时间在100h以内,则合金拉伸性能变化也不大;若热暴露时间超过100h,则合金强度和塑性均有所下降。于175℃热暴露500h屈服强度和伸长率就分别降低14%和9%;于热暴露条件下,2124-T851合金拉伸性能衰退的主要原因是合金固溶体基体内主要强化相S′(Al2CuMg)相粗化以及晶界无沉淀析出带的宽化。 The microstructures and mechanical properties of 2124-T851 aluminum alloy with the thickness of 30 mm under different thermal exposured conditions were investigated by tensile test, optical microscopy and transmitted electron microscopy. The results show that thermal exposured above last aging temperature 190℃ of the studied alloy, the strength of the alloy decreases and the elongation of the alloy increases. The higher the temperature and the longer the exposure time, the faster the strength decreases and elongation increases. Thermal exposured at 250 ℃ for 50 h and 100 h, the yield strength decreases by 53% and 58%, and the elongation increases by 23% and 55%, respectively. When thermal exposure is made at below last aging temperature, if the temperature is lower 150℃, the tensile properties of the alloy have no obvious change. When thermal exposure temperature approaches the last aging temperature and exposure time not so long, for example, at 175 ℃ for 100 h, the tensile properties of the alloy have also no large change, but if the exposure time is over 100 h, the strength of the alloy and the elongation of the alloy both decrease. Thermal exposured at 175 ℃ for 100 h and 500 h, the yield strength decreases by 5.5% and 14%, and the elongation decreases by 4% and 9.3%, respectively. The fact that S＇ （Al2CuMg） precipitates get coarsen and the precipitate-free-zones （PFZ） get wider are responsible for the decline of the tensile properties of 2124-T851 aluminum alloy under thermal exposure condition.
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