Relief of the residual stresses in Si₃N₄/Invar joints by multi-layered braze structure - Experiments and simulation

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• 作者：Tianpeng Wang^a ; Toni Ivas^b ; Wookjin Lee^c ; Christian Leinenbach^b ; Jie Zhang^a ; ^{hitzhangjie@hit.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Si3N4 ceramic ; Brazing ; Finite element simulation ; Residual stress
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：1 May 2016
• 年：2016
• 卷：42
• 期：6
• 页码：7080-7087
• 全文大小：2791 K

文摘

An Ag–Cu–Ti+TiNp/Cu/Ag–Cu three-layered filler was designed to braze Si₃N₄ ceramic and Invar alloy. The effect of the Cu-foil thickness on the microstructure and the mechanical properties of the brazed joints was investigated. Compared with single-layer Ag–Cu–Ti+TiNp filler, the formation of Fe₂Ti and Ni₃Ti compounds is widely inhibited by using multi-layered filler. The shear strength of the brazed joint is 47.9% higher than that of joints brazed with single Ag–Cu–Ti+TiNp filler when a 200 μm thick Cu interlayer is used. A simplified unit cell model was designed to obtain the physical properties of the TiNp reinforced filler. The model provides the elastic modulus and yield stress that satisfy the Hashin–Shtrikman bounds and N. Ramakrishnan׳s equations, respectively. In the three-layered brazing, the finite element (FE) model shows that system residual stresses decrease significantly by increasing the thickness of Cu foil in the multi-layered system.