Solid-state additive manufacturing of aluminum and copper using additive friction stir deposition: Process-microstructure linkages
Solid-state additive manufacturing of aluminum and copper using additive friction stir deposition: Process-microstructure linkages
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DOI：
10.1016/j.mtla.2020.100967
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发表时间：
2021-03-01
期刊：
影响因子：
3.4
通讯作者：
Yu, Hang Z.
中科院分区：
文献类型：
--
作者：
Griffiths, R. Joey;Garcia, David;Yu, Hang Z.
在金属增材制造技术中，增材摩擦搅拌沉积因其能够在不熔化和凝固的情况下创建自由形式和全致密结构而脱颖而出。在这里，我们采用比较的方法来研究添加剂摩擦搅拌沉积的过程中的微观结构的联系，利用两种材料具有不同的热机械行为的铝镁硅合金和铜，这两者都是具有挑战性的打印使用基于光束的添加剂工艺。沉积的Al-Mg-Si显示出具有广泛的亚晶形成和强剪切织构的相对均匀的显微组织，而沉积的Cu的特征在于晶粒尺寸的宽分布和较弱的剪切织构。结果表明，Al-Mg-Si合金的显微组织主要是通过连续动态再结晶（包括几何动态再结晶和渐进式晶格旋转）演化的，而Cu合金的异质组织是由沉积和冷却过程中的不连续再结晶形成的。在Al-Mg-Si中，连续再结晶随着施加应变的增加而进行，这与工具旋转速率O和移动速度V之间的比率相关。相反，发现Cu中的显微组织演变对O的依赖性较小，而随着V的变化而变化。这种差异源于沉积区中没有Cu旋转，这减小了工具旋转对应变发展的影响。我们属性的独特的工艺-微观结构的联系和Al-Mg-Si和Cu之间的潜在机制，其内在的热机械性能和相互作用的工具头的差异。
Among metal additive manufacturing technologies, additive friction stir deposition stands out for its ability to create freeform and fully-dense structures without melting and solidification. Here, we employ a comparative approach to investigate the process-microstructure linkages in additive friction stir deposition, utilizing two materials with distinct thermomechanical behavior-an Al-Mg-Si alloy and Cu-both of which are challenging to print using beam-based additive processes. The deposited Al-Mg-Si is shown to exhibit a relatively homogeneous microstructure with extensive subgrain formation and a strong shear texture, whereas the deposited Cu is characterized by a wide distribution of grain sizes and a weaker shear texture. We show evidence that the microstructure in Al-Mg-Si primarily evolves by continuous dynamic recrystallization, including geometric dynamic recrystallization and progressive lattice rotation, while the heterogeneous microstructure of Cu results from discontinuous recrystallization during both deposition and cooling. In Al-Mg-Si, the continuous recrystallization progresses with an increase of the applied strain, which correlates with the ratio between the tool rotation rate Oand travel velocity V. Conversely, the microstructure evolution in Cu is found to be less dependent on O, instead varying more with changes to V. This difference originates from the absence of Cu rotation in the deposition zone, which reduces the influence of tool rotation on strain development. We attribute the distinct process-microstructure linkages and the underlying mechanisms between Al-Mg-Si and Cu to their differences in intrinsic thermomechanical properties and interactions with the tool head.