(1. 中國兵器工業(yè)第五九研究所，重慶 400039；
2. 南京航空航天大學 機電學院，南京210016)
摘 要: 對Al6061/20SiCw板材在單向拉伸和等雙向拉伸應力狀態(tài)下的孔洞行為進行研究。利用長軸與短軸比分別為1׃1和2׃1的脹形模具，在恒定應力2 MPa，溫度873 K的條件下，研究Al6061/20SiCw板材的成形極限。基于MARCHINIAK-KUCAYNSKI(M-K)模型和塑性損傷模型，提出一種用于預測Al6061/20SiCw板材在雙向拉伸應力狀態(tài)下的極限應變的分析模型。結果表明：在相似的等效應變速率下，等雙向拉伸應力產生的孔洞數(shù)量稍多于單向拉伸應力產生的孔洞數(shù)量；對于無初始幾何缺陷的Al6061/20SiCw板材，分析模型能較為準確地預測復合材料在雙向拉伸條件下的極限應變。
關鍵字: 鋁基復合材料；超塑性；孔洞；成形性
（1. No. 59 Research Institute of China Ordnance Industry, Chongqing 400039, China;
2. School of Electromechanical Engineering, Nanjing University of Aeronautics and Astronautics,
Nanjing 210016, China）
Abstract: The cavitation behaviors of Al6061/20SiCw sheet under uniaxial and equibiaxial tension stress states were investigated. The forming limits of Al6061/20SiCw sheet under biaxial tension using dies with aspect ratios of 1:1 and 2:1 at constant applied stress of 2 MPa and at 873 K were also investigated. An analytic model based on the MARCHINIAK- KUCAYNSKI(M-K) and plastic damage models was proposed to predict the limiting strains of Al6061/20SiCw sheet under biaxial tension stress state. The results show that at a similar effective strain rate, the amount of cavities obtained under equibiaxial tension states is slightly greater than that under uniaxial tension states. Under the condition of Al6061/20SiCw sheet without original geometric deficiency, the prediction of the analytic mode is in agreement with the limiting strains under biaxial tension state.
Key words: aluminum-based composite; superplasticity; cavitation; formability
