(中南大學(xué) 粉末冶金國家重點實驗室, 長沙 410083)
摘 要: 設(shè)計了鋁合金鑄軋工藝模擬的實驗裝置，研究了在該試驗條件下， 鋁合金變形組織與工藝參數(shù)的關(guān)系。 結(jié)果表明： 按照本試驗的設(shè)計， 在夾頭通水冷卻的Gleeble-1500熱模擬機上能夠得到鋁的“人”字形特征的柱狀晶組織， 實現(xiàn)鑄軋組織的物理模擬過程。 鋁合金模擬鑄軋的顯微組織對外力施加的應(yīng)變速率很敏感： ε·=0.125s-1時， 變形開始與凝固過程發(fā)生耦合， 鑄軋組織發(fā)生轉(zhuǎn)變； 應(yīng)變速率增大至ε·=0.300s-1時， 鑄軋柱狀晶發(fā)生等軸化。 鑄軋組織的形成主要是變形作用于未凝固的液相，引起質(zhì)量和熱量的分布狀態(tài)發(fā)生改變所致。 提高鑄軋速度， 有利于鑄軋組織的形成和鑄軋柱狀晶的等軸化， 并且使所需的軋制力減小， 有利于鑄軋工藝的優(yōu)化。
關(guān)鍵字: 鋁合金；鑄軋； 物理模擬； 顯微組織
（State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract:An experimental instrument for simulating the roll-casting process was designed, and the effect of processing parameters on the microstructure of Al alloy was studied. Results show that with a specifically designed instrument equipped in a Gleeble-1500 Thermal Simulation Tester the typical microstructure with the characteristic of realistic roll-casting process can be obtained, and the microstructure is sensitive to the strain rate. When ε·=0.125s-1, the plastic deformation of Al alloy starts to couple with the solidification process, and the microstructure is of the roll-casting character. Whenε·=0.300s-1, the column crystals transform to equiaxed ones. The formation of roll-casting microstructure is mainly attributed to the deformation of un-solidified liquid phase, the varied distribution of mass and heat. Increasing the deformation velocity would do good to the formation of roll-casting microstructure and the equiaxed column crystals, and would decrease the rolling load.
Key words: roll-casting; Al alloy; physical simulation; microstr
