Olshanskaya Tatyana, Fedoseeva Elena
Department of Welding Production, Metrology and Technology of Materials, Perm National Research Polytechnic University, 614990 Perm, Russia.
Materials (Basel). 2022 Jan 4;15(1):348. doi: 10.3390/ma15010348.
This work is about the study of the correlation of pore formation in welded joints of Al-MG-LI alloy with zirconium additives with the state of the base metal, thermal vacuum treatment, and welding technologies MIG and EBW. Metallographic analysis has been carried out, the phase composition of the alloy and weld metal has been investigated, and thermal cycles of welding have been calculated, allowing to estimate the residence time of metal in the alloying zone and weld metal in the liquid state. The nature of the allocation of strengthening fine-dispersed phases in the welded joints of the alloy has been determined. The regularity and character of pore formation in welded joints depending on the applicable thermal vacuum treatment (TVT) and welding technology have been revealed. It was established that TVT with subsequent hardening and aging has no effect on the phase composition of the alloy. However, this type of treatment contributes to the formation of a more homogeneous and uniform nature of the separation of fine-dispersed strengthening phases. It was revealed that the MIG technology (metal with and without TVT) is characterized by a large length of the fusion zone, the high residence time of metal in the fusion zone and weld metal in the liquid state, and the formation of pores. Phase formation in the temperature range of the beginning and end of the alloy crystallization occurs not only in the weld at the final stage of crystallization but also in the fusion zone, which may induce pore formation, whereas EBW welding shows the opposite trend and no pores. It was found that EBW technology prevents pore formation and makes it possible to obtain welded joints of 1420 Al alloys of the required quality.
这项工作是关于研究添加锆的铝镁锂合金焊接接头中气孔形成与母材状态、热真空处理以及MIG和EBW焊接技术之间的相关性。进行了金相分析，研究了合金和焊缝金属的相组成，并计算了焊接热循环，从而能够估算金属在合金化区和液态焊缝金属中的停留时间。确定了合金焊接接头中强化细分散相的分布性质。揭示了焊接接头中气孔形成的规律和特征取决于所采用的热真空处理（TVT）和焊接技术。结果表明，随后进行淬火和时效的TVT对合金的相组成没有影响。然而，这种处理方式有助于形成更均匀一致的细分散强化相分离性质。结果表明，MIG技术（有或没有TVT的金属）的特点是熔合区长度大、金属在熔合区和液态焊缝金属中的停留时间长以及气孔形成，合金结晶开始和结束温度范围内的相形成不仅发生在结晶末期的焊缝中，也发生在熔合区，这可能导致气孔形成，而EBW焊接则呈现相反趋势且无气孔。结果发现，EBW技术可防止气孔形成，并能够获得所需质量的1420铝合金焊接接头。
