Effect of Current Pulsation on Weld Microstructure During Micro-Plasma Arc Welding of Inconel 718
Effect of Current Pulsation on Weld Microstructure During Micro-Plasma Arc Welding of Inconel 718
复制标题
Inconel 718微等离子弧焊电流脉动对焊缝组织的影响
DOI：
10.1007/978-981-16-0182-8_13
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
S. Bag
中科院分区：
文献类型：
--
作者：
A. Sahu;S. Bag
采用恒电流和脉冲电流两种方式对718高温合金进行微束等离子焊接。在凝固的焊缝熔合区中形成富Nb的Laves金属间化合物对焊缝机械性能具有不利影响。研究了脉冲电流对焊缝组织形貌、Laves相的形成及其对力学性能的影响。由于凝固过程中枝晶间形成了二次Laves相，焊接试样的拉伸性能不如母材。PC模式焊缝的硬度和拉伸性能比CC模式焊缝有明显的提高。与恒流焊接模式相比，脉冲电流焊接的拉伸延展性显示出显著的改善（47%）。脉冲电流的施加改变了熔合区的凝固方式，提高了焊缝的冷却速度，导致熔合区组织细化。熔合区细化减少了Nb在枝晶间区域的偏析，并且另外减少了Laves相形成的幅度。
The current investigation focused on micro-plasma welding of superalloy 718 by constant current (CC) and pulse current (PC) mode. Formation of Nb enriched Laves intermetallic in the solidified weld fusion zone has detrimental impact on the weld mechanical properties. The influence of current pulsation on the weld microstructural morphology, formation of Laves phase, and its consequence on mechanical properties are meticulously studied herein. The tensile characteristics of the welded samples are observed to be inferior to the parent material due to formation of secondary Laves phase in the interdendritic region during solidification. PC mode weld have shown enhancement in hardness and tensile characteristics against the CC mode weld. The tensile ductility has shown significant improvement (47%) with the application of pulse current as compared to constant current mode of welding. Application of pulse current changes the mode of solidification in the fusion zone and enhance weld cooling rate, that leads to the refinement of fusion zone microstructure. The fusion zone refinement reduces the segregation of Nb in the interdendritic region and additionally curtails the magnitude of Laves phase formation.