(1. 廣東省工業(yè)技術(shù)研究院(廣州有色金屬研究院) 金屬加工與成型技術(shù)研究所，廣州 510650；
2. 中南大學 材料科學與工程學院，長沙 410083)
摘 要: 采用鑄鍛復合一體化成形6061鋁合金，研究啟鍛時間對6061鋁合金的凝固、補縮、顯微組織和力學性能的影響。結(jié)果表明：靠近鍛壓沖頭面6061鋁合金為流線變形組織，中間部位晶粒則被壓扁壓實，靠近下模部分的合金晶粒在模具激冷作用下得到細化。當啟鍛時間為3~4 s時，鍛壓作用能夠?qū)辖疬M行強制性補縮和壓實組織，并產(chǎn)生塑性變形，避免了縮孔、裂紋和組織疏松等缺陷出現(xiàn)。隨著啟鍛時間的延長，熱處理前后鑄鍛件的抗拉強度和伸長率先增大再趨于平緩和減小，當啟鍛時間為4 s時，6061鋁合金鑄鍛件的拉伸力學性能達到最高，未熱處理的抗拉強度和伸長率分別為211.1 MPa和17.6%，熱處理后的抗拉強度和伸長率分別為368.9 MPa和11.5%。
關(guān)鍵字: 6061變形鋁合金；鑄鍛復合一體化成形；啟鍛時間；強制補縮
（1. Institute of Materials Processing and forming technology, Guangdong General Research Institute of Industrial Technology (Guangzhou Research Institute of Non-ferrous Metals), Guangzhou 510650, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China.）
Abstract:The casting-forging integrated technology was adopted to prepare 6061 aluminum alloy. The effects of forging start-up time on solidification, feeding, microstructure and mechanical properties of 6061 aluminum alloy were investigated. The results show that the microstructure of 6061 aluminum alloy closed to forging punch surface is deformation microstructure. The grains of 6061 aluminum alloy in the middle part are crushed and compacted. The grains of 6061 aluminum alloy closed to the lower mold are refined due to the chilling effect by the mold. When the forging start-up time is 3-4 s, the shrinkage, cracks and loose tissue can be avoided, because the forging force can effectively carry out pressure feeding, and make structure compacted through the forced feeding and plastic deformation. With the increase of forging start-up time, the tensile strength and elongation of 6061 aluminum alloy with and without T6 heat treatment first increase and then decrease. The maximal mechanical properties of the 6061 aluminum alloy parts can be obtained when the forging start-up time is 4 s. The tensile strength and elongation of 6061 aluminum alloy without T6 heat treatment is 211.1 MPa and 17.6%, respectively. The tensile strength and elongation of 6061 aluminum alloy with T6 heat treatment is 368.9 MPa and 11.5%, respectively.
Key words: 6061 wrought aluminum alloy; casting-forging integrated technology; forging start-up time; forced feeding
