【摘要】 提出了一种工艺性能好并能将位错强化和其他强化机制有机结合的超高强7085铝合金制备技术路线,即先在固溶处理温度对7085铝合金进行预热,然后,进行铝合金冷却速度较快的大应变变形等通道转角挤压(ECAP)加工.结果表明,ECAP加工对7085铝合金产生的强化与所用模具的温度密切相关,与模具温度为400°C的ECAP加工相比,模具温度为室温的ECAP加工对7085铝合金的强化效果显著.基于Taylor公式的定量计算结果表明,该显著的强化主要不是来自于位错强化的增加,而是来自于其他强化机制(沉淀强化、晶界/亚晶界强化等)的作用.更多还原

【Abstract】 A new precedure to prepare ultra-high strength aluminum alloy was proposed.The procedure is carried out through subjecting the aluminum alloy pre-heated at solid solution treatment temperature to the large strain deformation(equal-channel angular pressing,i.e.ECAP) with appropriately quick cooling of the alloy.This approach can process low ductility aluminum alloy and has the potential of adding dislocation strengthening and other strengthening together to significantly strengthen the alloy.The experimental results show that the ECAP-resulted strengthening for the 7085 Al alloy pre-heated at solid solution treatment temperature is related with the temperature of the used ECAP die.Compared to the ECAP proceesing with the ECAP die temperature of 400 °C,the ECAP proceesing with the ECAP die temperature at room temperature leads to a considerable increase in strengthening.The theorical calculation based on Taylor equation on strength dislocation density relationship indicates that the dominant factor for leading to the considerable increase in strengthening is not dislocation strengthening increase,but other strengthening mechanisms that are believed to be precipitation strengthening and grain boundary/subgrain boundary strengthening.更多还原