(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 通过光学显微镜、透射电镜以及力学性能测试，研究均匀化制度对7050铝合金板材组织演变的影响。将合金固溶后在不同速率淬火，研究均匀化制度对该合金淬火敏感性的影响。结果表明：固溶后慢速率淬火过程中，平衡相η主要位于再结晶晶粒中Al3Zr粒子的相界、再结晶晶界、亚晶晶界以及亚晶中与位错交互作用的少量Al3Zr粒子上形核析出；均匀化时间较短时(室温，120 ℃/h升温至465 ℃，8 h)，合金中析出少量Al3Zr粒子，固溶后的试样发生完全再结晶，此时合金淬火敏感性最好，但硬度较低；延长保温时间至20 h(室温，120 ℃/h升温至465 ℃，20 h)，试样中析出大量Al3Zr粒子，但分布不均匀，从而导致轧制固溶后的试样依然明显再结晶，合金淬火敏感性较差；采用快速升温的双级均匀化制度((室温，120 ℃/h升温至465 ℃，20 h)+(475 ℃，8 h))，Al3Zr粒子有所长大，淬火敏感性最差；采用慢速随炉升温((室温，18 ℃/h升温至465 ℃)+(475 ℃，8 h))的双级均匀化制度，合金中将弥散析出大量细小的Al3Zr粒子，固溶后的再结晶得到有效抑制，较多η相在亚晶界上的非均匀形核析出在一定程度上增加了合金的淬火敏感性，但该制度处理的合金仍优于再结晶程度较高的快速升温双级均匀化制度的。
关键字: 7050铝合金；均匀化制度；Al3Zr；淬火敏感性；组织演变
of 7050 aluminum alloy plates
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The microstructure evolution of 7050 aluminum alloy plates after homogenization was studied by optical microscopy, transmission electron microscopy, hardness and electric conductivity measurements. The influence of such processing on the quenching sensitivity was investigated by different homogenization methods. The results show that the equilibrium η phase mainly precipitates at areas such as the grain boundaries, sub-grain boundaries, incoherent Al3Zr particles within the recrystallization region and some Al3Zr particles which interact with the dislocations during slow quenching. For short time homogenization treatment (RT, 120 ℃/h to 465 ℃, 8 h), the recrystallization is observed at most of the areas and the alloy shows good quenching sensitivity but low hardness. When the holding time increases to 20 h (RT, 120 ℃/h to 465 ℃, 20 h), the recrystallization would be partly inhibited with higher quenching sensitivity. The two-stage homogenization with fast heating rate ((RT, 120 ℃/h to 465 ℃, 20 h)+(475 ℃, 8 h)) can not improve the quenching sensitivity and the Al3Zr particles coarsen slightly. And when the ramp heating (RT, 18 ℃/h to 465 ℃+ 475 ℃, 8h) is concerned, the recrystallization is inhibited efficiently by finer size and higher density of Al3Zr particles，and the equilibrium η phase mainly precipitates at the sub-grain boundaries and some Al3Zr particles interact with the dislocations, in addition better quenching sensitivity is achieved.
Key words: 7050 aluminum alloy; homogenization treatment; Al3Zr; quenching sensitivity; microstructure evolution
