Microstructure Evolution of Athermal Solidification Zone and Its Effect on Mechanical Properties in Dissimilar Transient Liquid Phase Bonded Joint of IN718 Ni-Based Alloy/316LN Steel
Microstructure Evolution of Athermal Solidification Zone and Its Effect on Mechanical Properties in Dissimilar Transient Liquid Phase Bonded Joint of IN718 Ni-Based Alloy/316LN Steel
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DOI：
10.1007/s11665-023-07997-0
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发表时间：
2023-03
影响因子：
2.3
通讯作者：
Miao Yang;Teng Zhang;R. Ding;Z. Qiao;Chenxi Liu;Yong-chang Liu
中科院分区：
文献类型：
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作者：
Miao Yang;Teng Zhang;R. Ding;Z. Qiao;Chenxi Liu;Yong-chang Liu
采用BNi-2合金箔对IN 718镍基合金与316LN钢进行了1050 °C、不同连接时间的瞬时液相（TLP）连接。讨论了非热凝固区金属间化合物的形成过程、对接头力学性能的影响及接头断裂机理。讨论了ASZ对接头力学性能的影响。分析表明，ASZ中存在四种金属间化合物，即Ni 23 B6、Cr B、Ni-Si-B和Ni 3Si。此外，还将ASZ中析出相的形成过程归纳为以下4个阶段：（1）γ（Ni）固溶体，（2）γ（Ni）+Ni 23 B6 + Cr B，（3）γ（Ni）+Ni 23 B6 + Cr B + Ni-Si-B，（4）Ni 3Si固相转变。力学性能实验结果表明，ASZ中形成的金属间相造成了更大的应力集中，因此此类TLP接头的力学性能不佳。剪切试验后，接头中心线处存在大量金属间化合物的接头呈现脆性断裂特征。此外，TLP接头横截面的SEM图像显示，裂纹在ASZ中形核并沿着接头中心线扩展。当接头中心金属间化合物含量减少时，接头表现为韧性断裂。
Transient liquid phase (TLP) bonding of IN718 Ni-based alloy and 316LN steel was carried out using BNi-2 alloy foil at 1050 °C for diverse bonding time. The formation process of intermetallics in the athermal solidification zone (ASZ) and the effects of intermetallics on the mechanical properties of joints and how they break are discussed. The effect of ASZ on the mechanical properties of joints was discussed. The analysis showed four kinds of intermetallic phases in ASZ, which are Ni23B6, CrB, Ni-Si-B, and Ni3Si. Besides, the formation of precipitates in ASZ was summarized in the following four stages: (1)γ(Ni) solid solution, (2)γ(Ni) + Ni23B6+ CrB, (3)γ(Ni) + Ni23B6+ CrB + Ni-Si-B, and (4) Ni3Si via solid-state transformation. The experimental results of mechanical properties showed that the intermetallic phases formed in ASZ cause greater stress concentration, so the mechanical properties of this kind of TLP joint are not excellent. After the shear test, the joint with a large number of intermetallic compounds at the centerline of the joint showed the characteristic of brittle fracture. In addition, SEM images of the cross section of TLP joints showed that the crack nucleates in ASZ and propagates along the centerline of the joints. When the content of intermetallics at the centerline of the joint decreases, the joint shows ductile fracture.