Formation of intermetallic and its effect on the hardening of welding joint between vanadium alloy and Hastelloy X alloy after heat treatment
Formation of intermetallic and its effect on the hardening of welding joint between vanadium alloy and Hastelloy X alloy after heat treatment
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DOI：
10.1016/j.nme.2023.101389
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发表时间：
2023-02
影响因子：
2.6
通讯作者：
Shao-ning Jiang;Jingjie Shen;T. Nagasaka;T. Muroga;A. Sagara;S. Ohnuki;K. Hokamoto;W. Rao;S. Ta
中科院分区：
文献类型：
--
作者：
Shao-ning Jiang;Jingjie Shen;T. Nagasaka;T. Muroga;A. Sagara;S. Ohnuki;K. Hokamoto;W. Rao;S. Ta
采用爆炸焊接（EXW）和焊后热处理（PWHT）方法对钒基合金和哈氏合金X进行了焊接。研究了焊接接头中金属间化合物的形成及其对硬化的影响。从形貌上看，EXW焊接接头具有典型的波状界面，界面上存在不连续的旋涡。涡流处的横截面样品表明，在EXW和PWHT之后，在NH2和HX之间形成夹层。分析了中间层的组织演变及相应的硬度。显微组织观察表明，EXW后的中间层以固溶体形式存在，具有高密度位错。具有FCC结构的固溶体是钒合金和Hastelloy X合金的混合物。硬化是由于固溶体和位错。经500 °C焊后热处理后，中间层仍以固溶体形式存在，其化学成分与EXW后中间层的化学成分相似。位错密度略有降低，导致硬度较EXW后有所降低。700 °C以上热处理后，形成Ni3Ti金属间化合物，在900 °C时，其尺寸增大，密度降低，对硬度的贡献占主导地位。
Vanadium alloy and Hastelloy X alloy was jointed by explosive welding (EXW), followed by post-weld heat treatment (PWHT). The formation of intermetallic within the welding joint and its effect on hardening were investigated. In terms of morphology, the joint after EXW is characterized by typical waved interface with discontinuous vortex. The cross-sectional samples at the vortex indicate that an interlayer between NH2 and HX formed after EXW and PWHT. The microstructure evolution and corresponding hardness of the interlayer were analyzed. The microstructural observation showed that the interlayer after EXW exists as solid solution with high-density dislocations. The solid solution with a structure of FCC is a mixture of vanadium alloy and Hastelloy X alloy. The hardening is attributed to solid solution and dislocations. After PWHT at 500 °C, the interlayer still exists in the form of solid solution, whose chemical composition is similar with that at the interlayer after EXW. Dislocation density decreases a little, which causes lower hardness compared with that after EXW. After PWHT above 700 °C, Ni3Ti intermetallics form, whose size increases and density decreases at 900 °C, and make a dominant contribution to the hardness.