(1. 寧夏大學 機械工程學院，銀川 750021；
2. 寧夏大學 寧夏智能裝備CAE重點實驗室，銀川 750021)
摘 要: 采用宏觀檢測與顯微分析相結合的手段，研究不同停放時間下6061鋁合金的力學性能與微觀組織的變化規(guī)律。結果表明：停放時間對6061鋁合金的晶粒尺寸有較大影響，晶粒尺寸呈先增大后減小的趨勢；停放時間對6061鋁合金彈塑性變形過渡階段有較大影響，但對彈性及塑性階段變形的影響很小。6061鋁合金在停放為0~2 h時，力學性能無明顯變化，變形后試樣表面光滑，變形協(xié)調(diào)性較好；停放時間為12 h時，材料的抗拉強度和屈服強度降至最低，但伸長率提高，試樣表面呈橘皮形貌，變形均勻性較差；停放時間為24 h~15 d時，合金的強度回升并逐漸趨于穩(wěn)定。結果表明：隨著停放時間的增長，6061鋁合金斷口的韌窩直徑和深度不斷增加，第二相粒子的尺寸也不斷增大，形狀由球狀、帶狀逐漸轉(zhuǎn)變?yōu)榘鍫睢K狀。通過研究得到6061鋁合金滿足汽車結構強韌化需求，綜合性能最優(yōu)需求的停放時間為12~24 h。此研究結果能夠為6061鋁合金加工工藝優(yōu)化提供理論指導。
關鍵字: 6061鋁合金；停放時間；力學性能；微觀組織
（1. School of Mechanical Engineering, Ningxia University, Yinchuan 750021, China
2. Ningxia Key Laboratory of computer Aided Engineering Technology for Intelligent Equipment, Ningxia University, Yinchuan 750021, China）
Abstract:The dependence of the mechanical properties and microstructure of 6061 aluminum alloy under different quench delay time were investigated by the combination of macro-detection and micro-analysis. The results show that the quench delay time has a great influence on the grain size of 6061 aluminum alloy, and the grain size increases first and then decreases. The quench delay time has a great influence on the elastic-plastic transition deformation of 6061 aluminum alloy, but has little effect on the elastic deformation. The 6061 aluminum alloy has no obvious change in mechanical properties during quench delay time of 0-2 h. After deformation, the surface of the specimens is smooth and the deformation coordination is better. When the quench delay time is 12 h, the tensile strength and yield strength of the material are minimized, but the elongation increases. Meanwhile, the surfaces of the specimens show the appearance of orange peel and the deformation uniformity is poor. When the quench delay time is 12 h-15 d, the strength of the alloy rises and gradually stabilizes. The results of microscopic analysis show that, with the increase of quench delay time, the diameter and depth of the dimples of the 6061 aluminum alloy fracture increase, and the sizes of the second phase particles also increase. The shapes gradually change from spheres and ribbons to plates and blocks. The optimal quench delay time of 6061 aluminum alloy is 12-24 h. The research results can provide theoretical guidance for the optimization of 6061 aluminum alloy processing technology.
Key words: 6061aluminum alloy; quench delay time; mechanical properties; microstructure
