Ag-Zn-Al Solid-Phase Metal Joining for Dimensional Stability
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Solution Overview
Problem
Conventional soldering methods for joining metal members in high-temperature applications require a reducing atmosphere and result in dimensional instability due to molten material protrusion and void formation.
Innovation Solution
A metal jointed body composed of Ag—Zn—Al alloy layers on both sides of an Ag—Zn—Al alloy layer, joined through solid-phase diffusion without melting, using thin film layers of Zn and Ag to facilitate atomic diffusion and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soldering with high melting point is used for high-temperature operation, then joining strength is improved, but joining requires reducing atmosphere and equipment complexity increases
Solution Approach 1:
The invention changes the joining mechanism from melting-based (soldering) to solid-phase diffusion-based joining. By using Ag-Zn-Al alloy layers with specific composition ranges (Ag: 70-90 atom%, Zn: 5-20 atom%, Al: 5-20 atom%) and controlling thickness parameters, the material undergoes solid-phase diffusion at elevated temperatures without melting, eliminating the need for reducing atmosphere and complex equipment
Solution Approach 2:
The invention employs a composite alloy layer structure consisting of Ag-Zn-Al alloy layers with specific compositional ratios. This composite material design enables solid-phase diffusion joining with high joining strength while maintaining simplicity in the joining process and equipment requirements
2Ease of manufacture
If eutectic reaction is used to generate molten material, then joining is performed in atmosphere, but dimensional stability deteriorates due to protrusion of molten material
Solution Approach 1:
The invention changes the physical state and joining mechanism by preventing melting entirely. By selecting Ag-Zn-Al alloy compositions with specific ranges and controlling the joining temperature to remain below the melting point, the material undergoes solid-phase diffusion instead of eutectic melting, eliminating molten material protrusion and maintaining dimensional stability while still allowing atmospheric joining conditions
3Strength
If soldering is used for joining metal members, then joining strength is achieved, but void formation occurs and reliability decreases
Solution Approach 1:
The invention replaces the thermal-melting-based soldering mechanism with a solid-phase diffusion mechanism. By using Ag-Zn-Al alloy layers and controlling the joining process to occur in the solid state through diffusion, the method eliminates void formation associated with melting and solidification, achieving both high joining strength and improved reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves stable, dimensionally consistent joining with improved design freedom, reduced weight, and high reliability, even in humid environments, without the need for vacuum or reducing atmospheres, and reduces equipment costs.
Implementation Method 1
the metal jointed body is joined by solid-phase joining, and no protrusion of molten joining material occurs
Data Source
AI summary
Provided is a metal jointed body, joined by solid-phase joining in the atmosphere, in which no protrusion of molten joining material occurs, that improves dimensional stability. A metal jointed body is formed by (A) making Ag films of two metal laminated bodies opposed to each other, the metal jointed body being configured by sequentially laminating a Zn film and an Ag film on an Al substrate serving as a member to be joined, and (B) bringing the Ag films into contact with each other, then (C) heating is performed while pressurizing, and closely adhering and solid-phase joining the Ag films to each other. The completed metal jointed body is a portion where Al—Ag alloy layers are provided on both sides of an Ag—Zn—Al alloy layer to join the Al substrates to each other.