Growth Manner of Intermetallic Compounds at the Weld Interface of Steel/Aluminum Alloy Lap Joint Fabricated by a Defocused Laser Beam
Growth Manner of Intermetallic Compounds at the Weld Interface of Steel/Aluminum Alloy Lap Joint Fabricated by a Defocused Laser Beam
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DOI：
10.2320/matertrans.l-mra2007838
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发表时间：
2007-06
影响因子：
1.2
通讯作者：
Kwang-jin Lee;S. Kumai;Naonori Kawamura;N. Ishikawa;K. Furuya
中科院分区：
文献类型：
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作者：
Kwang-jin Lee;S. Kumai;Naonori Kawamura;N. Ishikawa;K. Furuya
采用间断焊接的方法，研究了离焦激光焊接过程中钢/铝合金搭接接头界面IMC的形成和生长方式。用透射电子显微镜衍射图分析和电子显微镜-X射线化学成分分析研究了焊缝界面的组织转变。结果表明，Al13Fe4和Al2Fe在焊接初期形成，Al5Fe2随后在Al13Fe4和Al2Fe之间形成。Al5Fe2的择优生长和突变生长形成了由粗大的Al5Fe2和Al13Fe4组成的IMC层。控制界面微观组织的主要因素是焊后热历史。随着能量密度的增加，IMC层厚度增加，结合强度降低。因此，较低的能量输入(在其他焊接条件固定的情况下，较高的焊接速度)被认为是有用的，以抑制焊接后热历史期间可能发生的层中IMC的突然晶粒长大。
An interrupted welding method was performed in order to investigate the formation and growth manner of IMC at the weld interface of steel/aluminum alloy lap joint during defocused laser beam welding. Microstructural transition at the weld interface was precisely investigated by both TEM diffraction pattern analysis and TEM-EDX chemical composition analysis. It was revealed that Al 13 Fe 4 and Al 2 Fe formed at the early stage of welding process, and the formation of Al 5 Fe 2 subsequently occurred between Al 13 Fe 4 and Al 2 Fe. Preferential and abrupt growth of Al 5 Fe 2 resulted in the IMC layer which was composed of coarse Al 5 Fe 2 and Al 13 Fe 4 . The dominant factor controlling the interfacial microstructure is considered to be the post-welding thermal history. Increase of energy density gave rise to an increment of the IMC layer thickness, and brought about reduced bonding strength. Therefore, lower energy input (higher welding speed when other welding conditions are fixed) is considered to be useful in order to suppress the abrupt grain growth of the IMCs in the layer which possibly occurred during the post-welding thermal history.