Relationship between Bonding Strength and Interface Edge Angle of Bonded Dissimilar Materials with Machined Free Surfaces

2017 ◽  
Vol 2017.25 (0) ◽  
pp. 804
Author(s):  
Reiichi TOKUMOTO ◽  
Takashi TOMINAGA ◽  
Eiichiriu YOKOI ◽  
Masayoshi TATENO
Author(s):  
Masayoshi Tateno ◽  
Yoshiaki Hagiwara ◽  
Kunio Kokubo

The focus of this study is to clarify the effect of the interface edge shape on the bonding strength of ceramic to metal joint. Each silicon nitride to copper joint plate with arc-shaped free surfaces edge was produced by Electric Discharge machining (EDM). The interface edge shape was characterized by defining the edge angle as a configuration angle between the interface plane and tangential line at the arc edge of the bonded interface. Each joint was bonded at high temperature using thin braze metal under vacuum and slowly cooled. Good fit was achieved at each bonded face in this process. The dependence of the bonding strength on the edge angle was experimentally clarified in Silicon nitride to Copper joint with arc-shaped free surfaces. The result shows that changing the edge angle from right angle improves bonding strength since it decreases residual stress near the interface edge. The highest bonding strength appears at the specific interface where the fracture pattern changes. It also shows that secondary machining, which cuts both edges into optimum geometrical conditions after bonding, can improve bonding strength.


Author(s):  
Masayoshi Tateno ◽  
Yohei Hatano ◽  
Kunio Kokubo

Selection of the optimum shape for interface edge can produce significant increases in the strength of bonded dissimilar materials such as ceramic to metal joints. The focus of this study is to clarify an effect of interface edge shape on bonding strength of ceramic to metal joint. Each plate Si3N4 to Ni joint with arc interface of convexity or concavity is produced by Electric Discharge machining. The arc interface is characterized by edge angle defined as a configuration angle between tangential line at the edge of the interface and the free surface of the ceramic. Each joint is bonded at high temperature by using thin braze metal under vacuum and slowly cooled. A good fit on each bonded face is achieved in this process. The dependence of the bonding strength on the edge angle is experimentally clarified. The result shows that changing the edge angle from the right angle improves the bonding strength since it decreases the residual stress near edge of the interface. The highest bonding strength always appears at the identical interface condition where fracture pattern changes. It appears that the optimum edge angle for obtaining the highest bonding strength depends on bonding temperature.


2019 ◽  
Vol 6 (3) ◽  
pp. 18-00561-18-00561 ◽  
Author(s):  
Syunsuke MURAOKA ◽  
Reiichi TOKUMOTO ◽  
Yuki NAKAYAMA ◽  
Takashi TOMINAGA ◽  
Masayoshi TATENO

2019 ◽  
Vol 6 (3) ◽  
pp. 18-00566-18-00566
Author(s):  
Reiichi TOKUMOTO ◽  
Syunsuke MURAOKA ◽  
Takashi TOMINAGA ◽  
Masayoshi TATENO

2018 ◽  
Vol 2018.26 (0) ◽  
pp. 203
Author(s):  
Syunsuke MURAOKA ◽  
Reiichi TOKUMOTO ◽  
Yuki NAKAYAMA ◽  
Takashi TOMINAGA ◽  
Masayoshi TATENO

2017 ◽  
Vol 2017.25 (0) ◽  
pp. 208
Author(s):  
Yuki NAKAYAMA ◽  
Takashi TOMINAGA ◽  
Eiichiro YOKOI ◽  
Masayoshi TATENO

2016 ◽  
Vol 2016.24 (0) ◽  
pp. 204
Author(s):  
Yuki NAKAYAMA ◽  
Takashi TOMINAGA ◽  
Eiichirou YOKOI ◽  
Masayoshi TATENO

1999 ◽  
Vol 586 ◽  
Author(s):  
Masayoshi Tateno ◽  
Yasushi Fukuzawa ◽  
Shigeru Nagasawa ◽  
Hiroshi Sakuta

ABSTRACTIn order to evaluate the practical strength of a joint and its fracture mode, it is important to find the stress distribution near the edge of the interface by analyses of strength and fracture. The index of stress singularity based on theoretical analysis is a useful tool to indicate the stress distribution.In this paper, investigations on the evaluation of the practical strength of bonded dissimilar materials based on the stress singularity are carried out. The secant stiffness module, which was used for plastics analysis, was applied to the evaluation of thermal elastoplastic behavior near the interface. Spherical conditions of the interface shape were used for the evaluation of stress behavior and the experiment of bonding strength. The relationship between the index of stress singularity, λ, and the practical strength of the bonded TiB2-Ni system was investigated by comparing theoretical λ, which was determined by substituting the secant stiffness module into Bogy's eigenequation, with the practical strength in the edge angle of the interface between 60° and 90° The correlation factor of the relationship between λ and the practical bonding strength of the TiB2-Ni system was found positive. These results show that the structural design of a geometrical interface which is getting a higher strength joint based on the index of stress singularity is verified experimentally.


MRS Advances ◽  
2020 ◽  
Vol 5 (33-34) ◽  
pp. 1765-1774
Author(s):  
Shunsuke Muraoka ◽  
Masayoshi Tateno

AbstractResidual stress can considerably weaken systems with ceramics-to-metal joints. Herein, we investigate the dependence of bonding strength and residual stress variation of a ceramics-to-metal joint system on the interface wedge angle and bonding temperature condition. First, disparity between large-scale displacement models with varying work-hardening parameters was confirmed using thermal elastoplastic Finite Element Method (FEM) analysis. Each interface wedge shape was set to a plane surface to compare FEM results to experimental results related to the effect of the interface wedge angle on the practical bonding strength. The experimental results were specifically for a system consisting of Si3N4-WC/TiC/TaC bonded to Ni plate. The effects of the wedge angle of the metal side on residual stress near the interface edge were numerically predicted using FEM models. The interface wedge angles for this model, φ1 and φ2, were defined using the configuration angle between the interface and free surfaces of both materials. The numerical results showed that the stress σr on the free surface of the ceramic side was concentrated near the interface edge at which discontinuity in the stress state is generated. Dependence of the residual stress variation on both the wedge angle and temperature conditions can be predicted. It was confirmed that the bonding strength improves with decreasing residual stress in geometrical conditions. Therefore, residual stress appears to be a predominant factor affecting bonding strength. The observed fracture pattern showed that the fracture originated near the interface edges, after which small cracks propagated on the ceramic side. The residual stress is presumed to dominate bonding strength as the fracture occurred near the interface edge of the ceramic side. Results showed that the maximum bonding strength appears at the geometrical condition where the fracture pattern changes to φ2 lower than 90° of joint bonded at 980 °C. Therefore, the optimum interface wedge angle depends on a combination of materials and bonding temperature conditions, because the weak point of the bonded joint system will affect the stiffness balance of both materials and the adhesion power of the bonded interface.


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