杨帆 裴世超 罗新蕊 陈宇翔 李宁宇 常永勤. 6061铝合金搅拌摩擦增材制造显微组织演变及力学性能[J]. 金属学报, 10.11900/0412.1961.2023.00220.

摘要 相关文章 Metrics 全文: PDF(1842 KB)   摘要: 搅拌摩擦增材制造(Friction stir additive manufacturing，FSAM)是一种先进的固相成形技术，目前研究主要集中在对铝镁等合金FSAM成形工艺进行参数优化减少缺陷，替代传统有热源的成形方式。对于成形过程中材料的微观组织演变研究相对较少，本工作以2 mm厚的6061铝板为基材，采用搅拌摩擦增材制造技术在垂直方向成功实现了多层无孔洞缺陷材料的构建。通过微观表征及性能测试研究了成形件沿构建方向的组织演变和力学性能变化规律。结果表明，成形区发生了动态再结晶，获得了细小的等轴晶粒，界面过渡区经历搅拌头的二次搅拌作用后晶粒进一步细化。成形区整体抗拉强度为母材强度的47.7%~55.3%，延伸率提高到母材的148.8%，上下板重叠界面由于经历多次热循环，力学性能较差。球状的α-Al(MnCrFe)Si在基体中起强化作用，FSAM过程中强化相的大量溶解是成形样力学性能大幅下降的主要原因。经过520℃固溶1 h和165℃时效18 h热处理后，成形样力学性能显著提高，硬度略高于母材，抗拉强度恢复到母材的87.2%~92.0%。 关键词 ： 搅拌摩擦增材制造,  Al-Si-Mg-Cu铝合金,  焊后热处理,  钩状缺陷,  晶粒异常长大     Abstract：Friction stir additive manufacturing (FSAM) is an advanced solid-phase forming technology based on the principle of friction stir. As no heat source is required, the FSAM process can avoid metallurgical defects during melting and solidification of the material. The FSAM also conserves energy and protects the environment. To replace the traditional forming technology with a heat source, current research aims to optimize the forming process parameters of aluminum and magnesium alloys. Similarly to the friction stir welding process, increasing the temperature in the FSAM process will dissolve part of the strengthening phase, coarsening the particles and softening the welding core area. In addition, during layer-by-layer stacking in FSAM, the stir tool will re-stir the previously formed area, introducing a new thermal cycle during the stirring process. Because the changes in the temperature and stress field are more complex in the FSAM process than in the friction stir welding process, the influence of microstructure evolution on the mechanical properties of materials in the FSAM process is worthy of investigation. In this study, a multilayer defect-free FSAM material was fabricated from 2-mm-thick 6061 aluminum alloy sheets. The microstructural evolution along the building direction was observed during the FSAM process to investigate its effect on the microhardness and tensile properties. Dynamic crystallization formed fine equiaxed grains in the stir zone, which were further refined after re-stirring in the overlapping interface regions. The tensile strength and elongation of the FSAM material were 47.7%–55.3% and 148.8% those of the base material, respectively. Multiple thermal cycling weakens the performance of the overlapping interface regions. The spherical α-Al(MnCrFe)Si phase plays a strengthening role in the matrix. Extensive dissolution of the strengthening phase during the FSAM process is mainly responsible for the performance deterioration of the FSAM material. After solution at 520℃ for 1 h and aging at 165℃ for 18 h, the properties of the FSAM material were largely improved: the hardness slightly increased from that of the base material and the tensile strength reached 87.2%–92.0% that of the base material. Key words： friction stir additive manufacturing    Al-Si-Mg aluminum alloy    post-weld heat treatment    hooking defects    abnormal grain growth 收稿日期: 2023-05-15      ZTFLH:  TG453.9   基金资助:国家自然科学基金;国家自然科学基金 服务 把本文推荐给朋友 加入引用管理器 E-mail Alert RSS 作者相关文章 杨帆 裴世超 罗新蕊 陈宇翔 李宁宇 常永勤 44.8K 链接本文: https://www.ams.org.cn/CN/Y0/V/I/0 [1] 逯世杰, 王虎, 戴培元, 邓德安. 蠕变对焊后热处理残余应力预测精度和计算效率的影响[J]. 金属学报, 2019, 55(12): 1581-1592. [2] 李永奎, 权纯逸, 陆善平, 焦清洋, 李世键, 孙忠海. TA15钛合金薄壁焊接件热处理校形研究*[J]. 金属学报, 2016, 52(3): 281-288. [3] 邸新杰, 邢希学, 王宝森. Inconel 625熔敷金属中δ相的形核与粗化机理*[J]. 金属学报, 2014, 50(3): 323-328. [4] 赵志浩,徐振,王高松,崔建忠. 微合金化4043铝合金焊丝焊接接头的组织与性能[J]. 金属学报, 2013, 49(8): 946-952. Viewed Full text Abstract Cited   Shared      Discussed