Experimental study on axial closed die rolling thermo-mechanical treatment of 6061 aluminum alloy

Yanhui YANG; Yifan LIU; Yangyang ZHANG; Yankai FENG; Boyan ZHANG; Zhengfei LIANG

doi:10.1051/jnwpu/20254320278

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Volume 43 / No 2 (April 2025)

JNWPU, 43 2 (2025) 278-284

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Issue		JNWPU Volume 43, Number 2, April 2025


Page(s)		278 - 284
DOI		https://doi.org/10.1051/jnwpu/20254320278
Published online		04 June 2025

JNWPU 2025, 43(2): 278–284

Experimental study on axial closed die rolling thermo-mechanical treatment of 6061 aluminum alloy

6061铝合金轴向辗压形变热处理试验研究

Yanhui YANG (杨艳慧)¹^,2, Yifan LIU (刘逸凡)¹, Yangyang ZHANG (张洋洋)³, Yankai FENG (冯彦凯)¹^,2, Boyan ZHANG (张博言)¹ and Zhengfei LIANG (梁正霏)¹

¹ School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China
² Chongqing Innovation Center, Northwestern Polytechnical University, Chongqing 401135, China
³ Technical Center, Fushun Special Steel Co., Ltd., Fushun 113001, China

Received: 9 April 2024

Abstract

The microstructure and mechanical properties of 6061 aluminum alloy were studied by using the aging treatment of 540 ℃/3 h solid solution+60% reduction axial closed die rolling+180 ℃/1.5-8 h. Comparison was made with the aging treatment of 60% reduction rolling+540 ℃/3 h solid solution+180 ℃/8 h. The results show that after axial closed die rolling thermo-mechanical treatment, the dislocation density of the aluminum alloy increases, the PFZ width decreases, and the spheroidized β″ phase appears. The aluminum alloy obtains good comprehensive mechanical properties at the aging time of 2.5 h, the yield strength of 333 MPa and the tensile strength of 359 MPa. As the aging time gets longer, little change took place in the grain size of the aluminum alloy, the granular Mg₂Si precipitates in the grain decrease, and a small amount of coarse granular Mg₂Si precipitates appear at the grain boundary. The dimple at the tensile fracture gradually changes from large and deep to small and shallow, and the ductility of the aluminum alloy decreases with the aging time.

摘要

以540 ℃/3 h固溶+60%压下量轴向辗压+180 ℃/1.5~8 h时效的6061铝合金为研究对象, 通过与60%压下量镦粗+540 ℃/3h固溶+180 ℃/8 h时效处理对比, 研究了合金的组织和力学性能。结果表明: 进行轴向辗压形变热处理后, 合金内的位错密度增大, 无沉淀析出带(PFZ)宽度有所减小, 出现球化β″相; 合金在时效时间2.5 h时获得较好的综合力学性能, 屈服强度为333 MPa, 抗拉强度为359 MPa。随着时效时间延长, 合金的晶粒尺寸变化不大, 晶粒内部的颗粒状Mg₂Si析出相有所减少, 晶界上出现少量粗大的颗粒状Mg₂Si析出相; 拉伸断口处韧窝由大而深逐渐转变为小且浅, 合金的塑性随着时效时间的增加呈下降趋势。

Key words: 6061 aluminum alloy / thermo-mechanical treatment / axial closed die rolling / mechanical properties / microstructure

关键字 : 6061铝合金 / 形变热处理 / 轴向辗压成形 / 力学性能 / 显微组织

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

6061合金具有成形性好、耐蚀性强、强度高、耐高温性能好等优点, 被广泛应用于航天航空、汽车制造、轨道交通等领域[1–2]。形变热处理(thermo-mechanical treatment, TMT)是一种将变形和热处理有效结合的工艺, 通过析出强化和形变强化相结合提高合金强度, 可以达到高强度、高韧性的良好配合[3]。热处理过程中进行冷变形对后续时效过程中析出相的影响十分复杂[4], 高密度的位错会为时效析出提供形核位置及形核能; 同时, 新相的析出往往钉扎在位错、层错等缺陷上, 使其运动过程受阻, 从而提高合金的强度[5]。薛克敏等[6]研究了7034铝合金往复挤压与固溶时效处理后的微观组织和力学性能, 发现往复挤压变形后合金内的晶粒细化, 位错密度增大, 溶质扩散速率提升, 有利于后续固溶过程中粗大第二相的回溶和时效过程中MgZn₂相的析出; 赵漫[7]研究了2024铝合金经20%~90%的冷轧变形和时效处理样品的微观组织及性能, 发现20%冷轧变形后进行较低温度峰时效处理会析出弥散细小分布S相, 强度与塑性同时提高, 析出强化作用显著。

TMT工艺通常采用镦粗或冷轧变形。西北工业大学经过大量试验, 在压扭复合变形基础上研发了轴向辗压(axial closed die rolling, ACDR)设备与相关技术。该设备具有运动模式简单的特点, 工件成形时下模在齿轮传动下发生周向主动转动, 通过静摩擦带动工件旋转, 在滚动摩擦的作用下使上模(锥角模)发生被动旋转; 同时, 上模在液压传动下进行轴向进给, 促使其对工件实现连续局部滚压[8]。即在常规镦粗变形同时复合扭转变形, 可以使铝合金在相同压下量下产生更大的塑性变形。采用该设备和技术, 郑勇[8]对钛合金盘件进行轴向辗压热成形, 分析了其压缩行为及扭转行为, 明确了局部塑性变形区演变规律; 王海等[9]发现利用轴向辗压成形制造30Si2MnCrMoVE盘件时, 盘件的组织均匀性优于镦粗变形, 且轴向辗压成形过程促进了再结晶。

本文针对轴向辗压变形的形变热处理工艺对6061铝合金显微组织、力学性能及时效析出行为的影响进行了试验研究, 可为高性能6061铝合金成形工艺优化设计及组织性能的调控提供依据。

1 试验材料和方法

试验材料为6061铝合金铸锭, 如图 1所示, 其主要化学成分如表 1所示。从铸锭上切取轴向辗压形变热处理试样, 试样形状及尺寸如图 2所示。试样先经540 ℃下固溶保温3 h, 后水冷至室温; 之后再在室温下进行轴向辗压变形; 最后进行180 ℃下时效处理。其中, 轴向辗压变形在装备了轴向辗压装置的315T液压机[10]上完成, 其上模倾角为6°、轴向压下速度为5 mm/s、下模转速为1 rad/s, 压下量为60%。为研究轴向辗压冷变形对合金时效行为影响, 将变形后试样切割成四等份, 切分后的试样在180 ℃下进行时效, 保温时间分别为1.5, 2.5, 5, 8 h。

图1

轴向辗压试样形状与尺寸图(单位：mm)

图2

拉伸试样加工试块取样图(单位：mm)

另外, 为了与轴向辗压形变热处理工艺进行对比, 从相同铸锭上切取Ø80 mm×60 mm的圆柱试样进行传统镦粗变形及固溶时效热处理试验。试验过程及其主要参数为: 镦粗变形温度为520 ℃, 压下量为60%;变形后的试样在540 ℃下固溶保温3 h, 水冷后在180 ℃下时效保温8 h。

时效后的轴向辗压试样和镦粗试样分别沿弦向和径向切取Ø8 mm×55 mm试块, 并加工获得室温拉伸试样, 试块取样位置及室温拉伸试样加工方案分别如图 2~3所示。采用Instron3382电子万能材料试验机进行拉伸试验, 拉伸速率为2 mm/min。

图3

室温标准拉伸试样尺寸(单位：mm)

采用OLMPUS光镜观察拉伸试样夹持端的显微组织, 取样位置如图 3中红色虚线所示, 其中弦向拉伸试样选择靠近盘件边缘的夹持端; 随后采用FEI 200X场发射透射电子显微镜进行拉伸试样夹持端TEM组织观察, 使用电解双喷减薄方法制备薄膜样品, 电解液为30%的硝酸甲醇溶液; 采用TESCAN VEGA 3 LMU场发射扫描电子显微镜观察拉伸试样夹持端析出相形貌与拉伸断口微观形貌。

表1

6061合金主要化学成分 %

2 结果与分析

2.1 显微组织

图 4给出了6061铝合金试样轴向辗压形变热处理下时效1.5, 2.5, 5和8 h的弦向及径向显微组织照片。从图 4中可以看出, 试样的平均晶粒尺寸为190~230 μm, 时效时间对显微组织的平均晶粒尺寸影响不大。图 5给出了时效1.5 h与2.5 h后的轴向辗压形变热处理弦向试样的SEM图像。从图 5中可以看出, 在晶界及晶粒内部分布着形貌不同的析出相, 晶界上呈长条状, 晶粒内部呈颗粒状。根据析出相的EDS结果: Al质量分数为98.27%, Mg质量分数为0.74%, Si质量分数为0.99%[11], 可判断这些白色长条或颗粒状的析出相为Mg₂Si相。此外, 随着时效时间的延长, 晶粒内部的颗粒状的析出相有所减少, 晶界上出现少量粗大颗粒状的析出相。

图4

轴向辗压形变热处理下不同时效时间的显微组织

图5

轴向辗压形变热处理下时效时间1.5 h与2.5 h弦向的析出相形貌

2.2 拉伸力学性能

图 6给出了6061铝合金经镦粗-固溶-时效后室温力学性能结果。从图 6中可以看出, 拉伸曲线的整体趋势是应力随着应变迅速增加, 达到屈服点后发生加工硬化, 达到抗拉强度后发生颈缩, 直至断裂。此时, 径向试样的屈服强度为284 MPa; 抗拉强度为316 MPa; 弦向试样的屈服强度为292 MPa, 抗拉强度为318 MPa, 延伸率均为13%。

图6

镦粗-固溶-时效后的力学性能曲线

图 7给出了6061铝合金经不同时效时间的轴向辗压形变热处理后的拉伸曲线。从图 7可看出, 当时效时间为1.5 h时, 试样的强度较低, 延伸率相对较高, 随着时效时间延长, 试样的塑性逐渐降低, 强度呈先增高后降低趋势。当时效时间为2.5 h时, 试样获得较好的综合力学性能, 由于铝合金具有各向异性, 径向试样的抗拉强度为344 MPa, 屈服强度为322 MPa, 延伸率为8%; 弦向试样抗拉强度为359 MPa, 屈服强度为333 MPa, 延伸率为8%。通过轴向辗压形变热处理后, 试样强度大幅提升, 与镦粗-固溶-时效后试样相比, 屈服强度由284 MPa提高到322 MPa, 提高了约15%, 抗拉强度小幅提升。

图7

轴向辗压形变热处理下不同时效时间的室温拉伸曲线

结合6061铝合金时效过程中的析出序列, 对轴向辗压形变热处理过程进行分析: 固溶温度540 ℃时, 合金的能量逐渐升高, 会形成一定数量的空位, 并在淬火过程中保留下来。经过轴向辗压变形后, 合金的内部结构发生很大变化, 产生大量的空位和位错等。当发生动态回复时, 空位运动到表面及位错处消失, 或形成空位群。在时效初期, 铝合金基体的一部分晶面上聚集了Mg、Si原子, 形成溶质原子偏聚区(GP区), 与固溶体之间是共格关系, 球状的GP区与位错之间的交互作用会阻碍位错运动, 且位错也是时效第二相的优先形核位置, 形成的析出相也会阻碍合金的变形。随着变形量增大, 位错密度继续增加, 位错缠结更严重, 使试样的抗拉强度和屈服强度增大[12]。随着时效时间延长, 在峰值时效时会析出大量细小的析出相阻碍位错运动; 继续延长时效时间, 合金处于过时效状态, 过饱和固溶体中会析出大量分布不均匀的粗大片状析出相, 所以强度相较于峰值时效略有下降, 延伸率明显降低。

2.3 断口形貌

图 8给出了6061铝合金试样在轴向辗压形变热处理下时效1.5, 2.5, 5和8 h的径向及弦向拉伸断口SEM照片。可以看出, 同时效时间下不同方向的试样拉伸断口形貌均为微孔聚集型韧性断裂。当时效时间为1.5 h时, 韧窝尺寸约30~40 μm, 部分韧窝内分布着尺寸较小的析出相颗粒, 原因是在轴向辗压冷变形时6061铝合金中仍保留着较高的位错密度, 而位错集中区域易形成断裂源, 所以断裂源的数量较多, 致使断裂时难以形成较大尺寸的韧窝[13], 如图 8a)~8e)示。时效时间延长至2.5 h时, 可见明显的撕裂棱, 有解理特征, 为脆性断裂区, 塑性相对于时效时间为1.5 h时有所下降, 较均匀分布较大尺寸的析出相颗粒, 如图 8b)~8f)所示。继续延长时效时间, 当时效时间为5 h时, 韧窝数量明显减少, 且分布较浅, 韧窝尺寸约40 μm, 韧窝内析出相的尺寸明显增加, 尺寸约为10 μm, 塑性下降, 如图 8c)~8g)所示。直至时效时间为8 h时, 平坦台阶数量增加, 有着明显的沿晶断裂, 可见少量分布的小型韧窝, 深度较浅, 塑性明显下降, 表明在时效时间为8 h时, 试样有着更为明显的脆性断裂特征, 如图 8d)~8h)所示。从断口的分析结果可看出, 形变热处理的试样由于冷变形时加工硬化作用, 韧窝由大而深逐渐转变为小且浅, 合金的塑性随着时效时间增加呈下降趋势, 这与拉伸试验结果一致。

图8

轴向辗压形变热处理下不同时效时间的断口形貌

2.4 TEM组织分析

图 9给出了6061铝合金镦粗-固溶-时效与轴向辗压形变热处理时效2.5 h后试样的位错组态。从图 9a)中可知经过镦粗-固溶-时效处理, 合金内部存在少量的位错。镦粗-固溶-时效处理后试样内主要为GP区[14], 对位错的钉扎作用不显著, 位错可以自由运动, 位错密度较低。此外, 在镦粗-固溶-时效试样中形成了无沉淀析出带(PFZ), 且PFZ较宽, 宽度为86 nm。其形成原因是晶界处缺陷较多, 为析出相提供了足够高的形核能和形核质点, 析出相易于在位错塞积处形核, 并通过吸收周围的溶质原子长大, 从而降低基体中溶质原子浓度, 使析出相的形核驱动能下降, 从而在析出相处出现PFZ[15]。合金发生塑性变形时会优先在PFZ处发生塑性变形, 应力松弛, 当PFZ过宽时, 滑移带在晶界附近运动受阻, 很快会达到断裂极限并发生断裂[16], 过宽的PFZ会降低合金的力学性能。

图9

镦粗-固溶-时效与轴向辗压形变热处理时效2.5 h的位错组态

从图 9b)中可知经过轴向辗压冷变形后, 合金内位错密度显著增加, 位错呈网状较为均匀地分布。在变形过程中, 位错源产生的大量位错在切应力作用下沿着滑移面移动, 造成位错缠结, 形成位错胞; 大量位错在剪切应力作用下沿着滑移面运动, 当位错与晶界和析出相相遇时, 产生相互的交割作用, 位错缠结区明显, 形成少量的亚结构。由于冷变形会引起位错增殖, 位错密度的增加造成析出相直径减小, 而析出相直径越小强化效果越好, 位错密度对析出强化的贡献体现在细化析出相直径上, 位错密度提供了有利形核点促使析出相形核, 因此亚结构可以促进析出相的析出, 有利于提高力学性能[12]。同时PFZ的宽度有所减小, 约为65 nm, 也有利于改善合金的力学性能。

图 10给出了6061铝合金在镦粗-固溶-时效与轴向辗压形变热处理下时效2.5 h后试样的透射及选区衍射图像。从图 10a)中可知, 在镦粗-固溶-时效下, 试样的晶界平直清晰, 内部弥散分布着析出相。析出相为圆盘状β相与杆状β′相, 沿着[112]_Al晶带轴通常只能观察到其横截面, 衍射斑点参见图 10b), 此时β′相长度方向约为120~200 nm, 宽度方向约为90 nm; β相长宽尺寸约为200 nm。图 10c)~10d)给出了在轴向辗压形变热处理后试样的明场像及在近[111]_Al晶带轴方向上的透射及选区衍射结果。从图 10c)中可以看到球状β″相与杆状β′相, 此时β′相宽度方向约为20~60 nm, 长度方向约为200~300 nm。由于β″相的屈服极限比基体α-Al相高[17], 当累积变形达到一定程度后, β″相发生塑性变形, 由针状变为成细小颗粒, 并逐渐球化[18], 此时β″相的平均直径约为30 nm。与镦粗-固溶-时效相比, 固溶后引入轴向辗压冷变形后, 试样内部出现大量的位错, 同时在时效过程中析出相易于在位错上或周边聚集, 较高密度的位错和与基体半共格的纳米尺度β″相的交互作用提高了合金的强度[19], 且对改善塑性有着重要的作用[20]。

图10

镦粗-固溶-时效与轴向辗压形变热处理时效2.5 h下的透射及选区衍射图

3 结论

1) 轴向辗压形变热处理后的6061铝合金在晶界及晶粒内部分布较均匀的Mg₂Si析出相, 析出相在晶界上呈长条状, 晶粒内部呈颗粒状; 随着时效时间延长, 晶粒内部的颗粒状析出相有所减少, 晶界上出现少量粗大颗粒状的析出相。

2) 镦粗-固溶-时效处理后合金内部稀疏分布着β相和β′相, 存在少量的位错, PFZ的宽度为86 nm; 引入轴向辗压变形后, 合金内位错密度显著增加, PFZ的宽度有所减小, 出现球化β″相, 尺寸约为30 nm, 位错相互缠结形成位错胞, 纳米尺度的β″相与高密度位错相互作用, 改善了合金的力学性能。

3) 轴向辗压形变热处理工艺可以显著提高合金强度。随着时效时间延长, 试样强度呈先上升后下降趋势, 延伸率呈逐渐降低趋势; 当时效时间为2.5 h时, 试样的力学性能最优, 此时径向试样的抗拉强度为344 MPa, 屈服强度为322 MPa, 延伸率为8%;弦向试样的抗拉强度为359 MPa, 屈服强度为333 MPa, 延伸率为8%。拉伸断口形貌表明韧窝由深而大变为浅而小, 验证了力学性能的变化规律。

References

ZHONG Jing, ZHENG Ziqiao, SHE Lingjuan, et al. Effects of aging treatments on tensile properties and fracture toughness of AA6156 aluminum alloy[J]. Rare Metal Materials and Engineering, 2013, 42(10): 2163–2168 (in Chinese) [Google Scholar]
ENGLER O, HIRSCH J. Texture control by thermomechanical processing of AA6XXX Al-Mg-Si sheet alloys for automotive applications: a review[J]. Materials Science and Engineering A, 2002, 336(1/2): 249–262 [Google Scholar]
WANG Zhutang, TIAN Rongzhang. Aluminium alloy and its processing manual[M]. Changsha: Central South University Press, 2000 (in Chinese) [Google Scholar]
LIU Juan, LAN Jian. Solid solution-cold deformation-aging process of 2A14 aluminum alloy[J]. Heat Treatment of Metals, 2018, 43(7): 163–167 (in Chinese) [Google Scholar]
ZHANG Jishuai, CHEN Zhiguo, REN Jieke, et al. Effect of new thermomechanical treatment on microstructure and properties of Al-Zn-Mg-Cu aluminum alloy[J]. The Chinese Journal of Nonferrous Metals, 2015, 25(4): 910–917 (in Chinese) [Google Scholar]
XUE Kemin, ZHANG Junyuan, YAN Siliang, et al. Study on the strengthening and toughening mechanisms of 7034 aluminum alloy subjected to reciprocating extrusion based thermo-mechanical treatment[J]. Rare Metal Materials and Engineering, 2023, 52(9): 3089–3096 (in Chinese) [Google Scholar]
ZHAO Man. Effect of thermo-mechanical treatment on the microstructure and properties of 2024 aluminum alloy[D]. Chongqing: Chongqing University, 2021 (in Chinese) [Google Scholar]
ZHENG Yong. Kinematics laws of ACDR processing of titanium disc and its effect on microstructures and properties[D]. Xi'an: Northwestern Polytechnical University, 2018 (in Chinese) [Google Scholar]
WANG H, LIU D, ZHANG F, et al. A comparative study on the evolutions of thermal and mechanical parameters and microstructure of 30Si2MnCrMoVE steel during hot ACDR and upsetting deformation[J]. The International Journal of Advanced Manufacturing Technology, 2021, 114(1/2): 579–589 [Google Scholar]
ZHANG Yangyang. Study on the compression-torsion deformation and thermomechanical treatment of 6061 aluminum alloy[D]. Xi'an: Northwestern Polytechnical University, 2023 (in Chinese) [Google Scholar]
WANG Xiaoguo, ZHANG Xiaoyuan, SUN Ruijuan, et al. Hot deformation behavior of dispersion strengthened 6XXX Al alloy[J]. Special Casting & Nonferrous Alloys, 2021, 41(9): 1114–1118 (in Chinese) [Google Scholar]
MOSTAFA M, BAHMAN M. Influence of sequence of cold working and aging treatment on mechanical behaviour of 6061 aluminum alloy[J]. Transactions of Nonferrous Metals Society of China, 2012, 22(9): 2072–2079 [Article] [Google Scholar]
ISLAM M U, WALLACE W. Retrogression and reaging response of 7475 aluminum-alloy[J]. Metals Technology, 1983, 24(10): 386–392 [Google Scholar]
CHANG C S T, WIELER I, WANDERKA N, et al. Positive effect of natural pre-ageing on precipitation hardening in Al-0.44 at% Mg-0.38 at% Si alloy[J]. Ultramicroscopy, 2009, 109(5): 585–592 [Article] [Google Scholar]
ZHAN X, TANG J, LI H, et al. Effects of non-isothermal aging on mechanical properties, corrosion behavior and microstructures of Al-Cu-Mg-Si alloy[J]. Journal of Alloys and Compounds, 2020, 819: 152960 [Article] [Google Scholar]
PARK J K, ARDELL A J. Microchemical analysis of precipitate free zones in 7075-Al in the T6, T7 and RRA tempers[J]. Acta Metallurgica et Materialia, 1991, 39(4): 591–598 [Google Scholar]
CAI M, FIELD D P, LORIMER G W. A systematic comparison of static and dynamic ageing of two Al-Mg-Si alloys[J]. Materials Science and Engineering, 2004, 373(1/2): 65–71 [Google Scholar]
ZHANG Yong, LIU Manping, QIN Xi, et al. Research progress on microstructure of age-hardenable 6000 series aluminum alloys processed by severe plastic deformation[J]. Transactions of Materials and Heat Treatment, 2019, 40(6): 1–10 (in Chinese) [Google Scholar]
ROVEN H J, LIU M P, WERENSKIOLD J C. Dynamic precipitation during severe plastic deformation of an Al-Mg-Si aluminium alloy[J]. Materials Science and Engineering A, 2008, 483: 54–58 [Google Scholar]
SHA G, TUGCU K, LIAO X Z, et al. Strength, grain refinement and solute nanostructures of an Al-Mg-Si alloy(AA6060) processed by high-pressure torsion[J]. Acta Material, 2014, 12(63): 169–179 [Google Scholar]

All Tables

表1

6061合金主要化学成分 %

In the text

All Figures

	图1 轴向辗压试样形状与尺寸图(单位：mm)
In the text

	图2 拉伸试样加工试块取样图(单位：mm)
In the text

	图3 室温标准拉伸试样尺寸(单位：mm)
In the text

	图4 轴向辗压形变热处理下不同时效时间的显微组织
In the text

	图5 轴向辗压形变热处理下时效时间1.5 h与2.5 h弦向的析出相形貌
In the text

	图6 镦粗-固溶-时效后的力学性能曲线
In the text

	图7 轴向辗压形变热处理下不同时效时间的室温拉伸曲线
In the text

	图8 轴向辗压形变热处理下不同时效时间的断口形貌
In the text

	图9 镦粗-固溶-时效与轴向辗压形变热处理时效2.5 h的位错组态
In the text

	图10 镦粗-固溶-时效与轴向辗压形变热处理时效2.5 h下的透射及选区衍射图
In the text

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[1] ZHONG Jing, ZHENG Ziqiao, SHE Lingjuan, et al. Effects of aging treatments on tensile properties and fracture toughness of AA6156 aluminum alloy[J]. Rare Metal Materials and Engineering, 2013, 42(10): 2163–2168 (in Chinese) [Google Scholar]

[2] ENGLER O, HIRSCH J. Texture control by thermomechanical processing of AA6XXX Al-Mg-Si sheet alloys for automotive applications: a review[J]. Materials Science and Engineering A, 2002, 336(1/2): 249–262 [Google Scholar]

[3] WANG Zhutang, TIAN Rongzhang. Aluminium alloy and its processing manual[M]. Changsha: Central South University Press, 2000 (in Chinese) [Google Scholar]

[4] LIU Juan, LAN Jian. Solid solution-cold deformation-aging process of 2A14 aluminum alloy[J]. Heat Treatment of Metals, 2018, 43(7): 163–167 (in Chinese) [Google Scholar]

[5] ZHANG Jishuai, CHEN Zhiguo, REN Jieke, et al. Effect of new thermomechanical treatment on microstructure and properties of Al-Zn-Mg-Cu aluminum alloy[J]. The Chinese Journal of Nonferrous Metals, 2015, 25(4): 910–917 (in Chinese) [Google Scholar]

[6] XUE Kemin, ZHANG Junyuan, YAN Siliang, et al. Study on the strengthening and toughening mechanisms of 7034 aluminum alloy subjected to reciprocating extrusion based thermo-mechanical treatment[J]. Rare Metal Materials and Engineering, 2023, 52(9): 3089–3096 (in Chinese) [Google Scholar]

[7] ZHAO Man. Effect of thermo-mechanical treatment on the microstructure and properties of 2024 aluminum alloy[D]. Chongqing: Chongqing University, 2021 (in Chinese) [Google Scholar]

[8] ZHENG Yong. Kinematics laws of ACDR processing of titanium disc and its effect on microstructures and properties[D]. Xi'an: Northwestern Polytechnical University, 2018 (in Chinese) [Google Scholar]

[9] WANG H, LIU D, ZHANG F, et al. A comparative study on the evolutions of thermal and mechanical parameters and microstructure of 30Si2MnCrMoVE steel during hot ACDR and upsetting deformation[J]. The International Journal of Advanced Manufacturing Technology, 2021, 114(1/2): 579–589 [Google Scholar]

[10] ZHANG Yangyang. Study on the compression-torsion deformation and thermomechanical treatment of 6061 aluminum alloy[D]. Xi'an: Northwestern Polytechnical University, 2023 (in Chinese) [Google Scholar]

[11] WANG Xiaoguo, ZHANG Xiaoyuan, SUN Ruijuan, et al. Hot deformation behavior of dispersion strengthened 6XXX Al alloy[J]. Special Casting & Nonferrous Alloys, 2021, 41(9): 1114–1118 (in Chinese) [Google Scholar]

[12] MOSTAFA M, BAHMAN M. Influence of sequence of cold working and aging treatment on mechanical behaviour of 6061 aluminum alloy[J]. Transactions of Nonferrous Metals Society of China, 2012, 22(9): 2072–2079 [Article] [Google Scholar]

[13] ISLAM M U, WALLACE W. Retrogression and reaging response of 7475 aluminum-alloy[J]. Metals Technology, 1983, 24(10): 386–392 [Google Scholar]

[14] CHANG C S T, WIELER I, WANDERKA N, et al. Positive effect of natural pre-ageing on precipitation hardening in Al-0.44 at% Mg-0.38 at% Si alloy[J]. Ultramicroscopy, 2009, 109(5): 585–592 [Article] [Google Scholar]

[15] ZHAN X, TANG J, LI H, et al. Effects of non-isothermal aging on mechanical properties, corrosion behavior and microstructures of Al-Cu-Mg-Si alloy[J]. Journal of Alloys and Compounds, 2020, 819: 152960 [Article] [Google Scholar]

[16] PARK J K, ARDELL A J. Microchemical analysis of precipitate free zones in 7075-Al in the T6, T7 and RRA tempers[J]. Acta Metallurgica et Materialia, 1991, 39(4): 591–598 [Google Scholar]

[17] CAI M, FIELD D P, LORIMER G W. A systematic comparison of static and dynamic ageing of two Al-Mg-Si alloys[J]. Materials Science and Engineering, 2004, 373(1/2): 65–71 [Google Scholar]

[18] ZHANG Yong, LIU Manping, QIN Xi, et al. Research progress on microstructure of age-hardenable 6000 series aluminum alloys processed by severe plastic deformation[J]. Transactions of Materials and Heat Treatment, 2019, 40(6): 1–10 (in Chinese) [Google Scholar]

[19] ROVEN H J, LIU M P, WERENSKIOLD J C. Dynamic precipitation during severe plastic deformation of an Al-Mg-Si aluminium alloy[J]. Materials Science and Engineering A, 2008, 483: 54–58 [Google Scholar]

[20] SHA G, TUGCU K, LIAO X Z, et al. Strength, grain refinement and solute nanostructures of an Al-Mg-Si alloy(AA6060) processed by high-pressure torsion[J]. Acta Material, 2014, 12(63): 169–179 [Google Scholar]