Dissimilar Metal Solid-Phase Bonding Below Transformation Temperature
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Solution Overview
Problem
Current solid phase bonding methods for dissimilar materials often result in fragile intermetallic compounds at the bonding interface and struggle to achieve strong joints, especially when bonding materials with different compositions like steel and titanium, due to differing deformation behaviors and physical properties.
Innovation Solution
A method where dissimilar materials are bonded at a temperature where both members have substantially the same strength, with the bonding pressure set to be above the yield stress and below the tensile strength, using friction welding or resistance heating to control the bonding temperature and form new surfaces for strong bonding, while managing burr discharge to maintain accurate temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional friction welding is used for dissimilar materials, then bonding can be achieved, but fragile intermetallic compounds form at the bonding interface
Solution Approach 1:
The invention changes the bonding temperature parameter to be below the transformation point of the ferrous material, preventing intermetallic compound formation. By controlling the maximum bonding temperature to be equal to or less than the As point or Acm point of the ferrous material, the method achieves strong bonding without the harmful intermetallic compounds that typically form at higher temperatures.
Solution Approach 2:
The invention performs preliminary heating of one of the materials to be bonded before the actual bonding process. This preliminary action allows control over the bonding temperature and ensures that the temperature remains below the transformation point during bonding, preventing intermetallic compound formation while still achieving adequate bonding strength.
2Strength
If bonding temperature is increased to improve bonding strength, then stronger joints are achieved, but deformation behavior differences between materials worsen
Solution Approach 1:
The invention changes the bonding temperature parameter to a lower range (below the transformation point of the ferrous material) where both materials exhibit more similar deformation behaviors. This temperature control ensures that yield strength ratios between dissimilar materials remain closer, improving deformation coordination during bonding while still achieving adequate joint strength.
3Reliability
If solid phase bonding is used to lower bonding temperature, then intermetallic compound formation is reduced, but bonding strength becomes insufficient
Solution Approach 1:
The invention performs preliminary heating of one material before bonding to optimize the temperature distribution. This preliminary action ensures that during the actual bonding process, the temperature remains below the transformation point (preventing intermetallic compounds) while still achieving adequate bonding strength through controlled plastic deformation and interface contact.
Solution Approach 2:
The invention changes the bonding temperature parameter to a specific range below the transformation point, and combines this with pressure control to achieve both low temperature (preventing intermetallics) and adequate bonding strength through optimized plastic deformation at the interface.
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
This approach enables the efficient formation of robust bonded portions with improved mechanical properties by ensuring the bonding temperature is accurately controlled, preventing brittle martensite formation and achieving strong joints across dissimilar materials.
Implementation Method 1
friction welding in which a rotating columnar material to be bonded is pressed against a fixed material to be bonded
Implementation Method 2
resistance heating to control the bonding temperature
Data Source
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AI summary
The present invention provides dissimilar material solid phase bonding with which a robust bonded portion of metal materials having different compositions can be formed efficiently. The present invention also provides a dissimilar material solid phase bonded structure having a dissimilar material solid phase bonded portion in which metal materials having different compositions have been bonded together robustly. In the dissimilar material solid phase bonding method according to the present invention, one member is brought into contact with another member to form an interface to be bonded, and newly formed surfaces of the one member and the other member are formed at the interface to be bonded, by means of the application of a bonding load, characterized in that: the one member and the other member have different compositions; the temperature at which the one member and the other member have substantially the same strength is defined as a bonding temperature; and the bonding load at which strength is applied substantially perpendicular to the interface to be bonded is set.