(中南大學 材料科學與工程學院，長沙 410083)
摘 要: 通過光學顯微鏡、透射電鏡以及力學性能測試，研究均勻化制度對7050鋁合金板材組織演變的影響。將合金固溶后在不同速率淬火，研究均勻化制度對該合金淬火敏感性的影響。結果表明：固溶后慢速率淬火過程中，平衡相η主要位于再結晶晶粒中Al3Zr粒子的相界、再結晶晶界、亞晶晶界以及亞晶中與位錯交互作用的少量Al3Zr粒子上形核析出；均勻化時間較短時(室溫，120 ℃/h升溫至465 ℃，8 h)，合金中析出少量Al3Zr粒子，固溶后的試樣發(fā)生完全再結晶，此時合金淬火敏感性最好，但硬度較低；延長保溫時間至20 h(室溫，120 ℃/h升溫至465 ℃，20 h)，試樣中析出大量Al3Zr粒子，但分布不均勻，從而導致軋制固溶后的試樣依然明顯再結晶，合金淬火敏感性較差；采用快速升溫的雙級均勻化制度((室溫，120 ℃/h升溫至465 ℃，20 h)+(475 ℃，8 h))，Al3Zr粒子有所長大，淬火敏感性最差；采用慢速隨爐升溫((室溫，18 ℃/h升溫至465 ℃)+(475 ℃，8 h))的雙級均勻化制度，合金中將彌散析出大量細小的Al3Zr粒子，固溶后的再結晶得到有效抑制，較多η相在亞晶界上的非均勻形核析出在一定程度上增加了合金的淬火敏感性，但該制度處理的合金仍優(yōu)于再結晶程度較高的快速升溫雙級均勻化制度的。
關鍵字: 7050鋁合金；均勻化制度；Al3Zr；淬火敏感性；組織演變
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
