(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 湖南人文科技學(xué)院 機電工程系，婁底 417000)
摘 要: 采用拉伸與疲勞試驗、掃描電子顯微分析與透射電子顯微分析，研究不同熱機械處理條件下2E12鋁合金的拉伸力學(xué)性能、疲勞性能以及顯微組織結(jié)構(gòu)。結(jié)果表明：采用本熱機械處理可以使2E12合金同時獲得高強度與高塑性，在屈服強度達到453.1 MPa、抗拉強度高達546.9 MPa的同時，伸長率仍然保持在16.5%。當應(yīng)力比R=0.1，加載頻率f=10 Hz，應(yīng)力強度因子ΔK=10 MPa？m-1/2 時，熱機械處理樣品裂紋擴展速率約為6.74×10-5 mm/cycle，優(yōu)于T3狀態(tài)下的8.35×10-5 mm/cycle。顯微組織觀測結(jié)果表明：采取本新型熱機械處理后，合金中位錯密度較高且相互纏結(jié)，形成胞狀組織。新型熱機械處理大幅改善合金綜合性能的機制是高密度位錯胞狀組織、溶質(zhì)原子團簇及空位復(fù)合體、GPB區(qū)等復(fù)合組織結(jié)構(gòu)的協(xié)同作用。
關(guān)鍵字: 2E12鋁合金；熱機械處理；力學(xué)性能；顯微組織
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Department of Mechanical and Electrical Engineering, Hunan University of Humanities,
Science and Technology, Loudi 417000, China）
Abstract:The tensile test and fatigue crack propagation test, as well as scanning electron microscope and transmission electron microscope, were used to study the tensile properties, fatigue property and microstructure of 2E12 alloy under different thermo-mechanical treatment (TMT) conditions. The results indicate that both high strength and high plasticity of 2E12 alloy can be achieved by the means of TMT, the yield strength reaches 453.1 MPa, and the ultimate tensile strength reaches to 546.9 MPa, while a high elongation rate of 16.5% is retained. Under the condition of stress ratio R=0.1, loading frequency f=10 Hz, stress intensity factor ΔK=10 MPa？m-1/2, the fatigue crack growth rate of the TMT sample is 6.74×10-5 mm/cycle, lower than that of T3 alloy (8.35×10-5 mm/cycle). As the result of microstructure observation indicates, the thermo-mechanical processed alloy contains a high density of tangled dislocation, which forms dislocation cell substructure. The mechanism of the new TMT that greatly increases the mechanical properties of the alloy is the synergistic effect of composite structures such as a high density of cell substructure of dislocations, the complex of Mg-Cu solute atoms clusters and vacancies, as well as GPB zones.
Key words: 2E12 aluminum alloy; thermo-mechanical treatment; mechanical properties; microstructure
