(中南大學 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 在300~450 ℃溫度范圍內對2A14鋁合金進行恒應變速率的多向壓縮實驗，模擬其多向鍛造過程，采用金相顯微鏡(OM)、掃描電鏡(SEM)、透射電鏡(TEM)和室溫力學性能測試等手段研究變形溫度對2A14合金的顯微組織和力學性能的影響。結果表明：隨著變形溫度的升高，合金的軟化機制由動態(tài)回復向動態(tài)再結晶轉變，位錯密度隨之降低；變形后的2A14鋁合金在熱處理過程中，發(fā)生靜態(tài)再結晶，變形過程中累積的形變儲能對再結晶的形核及長大具有促進作用。隨著變形溫度的升高，時效態(tài)2A14鋁合金的平均晶粒尺寸隨之增大，分布變得不均勻，其強度與平均晶粒尺寸滿足Hall-Petch關系式；室溫拉伸斷口形貌表現(xiàn)出韌性斷裂特征，且隨著變形溫度的升高，單位面積內韌窩數(shù)量減少、尺寸增大，合金的塑性變差。
關鍵字: 2A14鋁合金；變形溫度；顯微組織；力學性能；多向壓縮
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083）
Abstract:The multi-axial compression tests of 2A14 aluminum alloy were carried out with a constant strain rate to simulate the multi-forging process in the temperature range from 300 to 450 ℃. The effects of hot deformation temperature on microstructure and mechanical properties of 2A14 aluminum alloy were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and mechanical property testing. The results show that, with the increase of the deforming temperature, the dislocation density decreases, and the softening behavior of the alloy transforms from dynamic recovery to dynamic recrystallization. The compressed samples have stored high deformation energy, which can supply driving force for nucleation and grain growth of static recrystallization during heat-treatment. With the increase of the deformation temperature, the average grain size of the aged alloy increases and presents uneven distribution, meanwhile, the relationship between the strength and average grain size meets the Hall-Petch equation. The microstructure of the fracture is consisted of a large number of equiaxed dimples, and with the increase of the deforming temperature, the number of dimples decreases while the size of dimples increases which indicates a toughness fracture mode during tensile testing.
Key words: 2A14 aluminum alloy; deformation temperature; microstructure; mechanical properties; multi-axial compression
