Bonded Article Heat Capacity Control for Dissimilar Metal Joining
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Solution Overview
Problem
The ring mash bonding method struggles to achieve effective bonding length and strength when bonding metal materials with different melting points and electrical resistances, as the material with a lower melting point undergoes excessive plastic flow while the higher melting point material's flow is insufficient, leading to undercuts and reduced bonding area.
Innovation Solution
Incorporating a heat capacity increasing portion near the bonding target portion of the metal with a lower melting point to regulate plastic flow, ensuring both materials bond effectively by applying a pressing force and current, with the heat capacity portion positioned to minimize early and excessive plastic flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If ring mash bonding is performed on metal materials with different melting points, then bonding area increases through plastic flow, but the material with lower melting point undergoes excessive plastic flow while the higher melting point material's flow is insufficient
Solution Approach 1:
The invention applies different surface conditions to different parts of the bonding target portion. Specifically, part of the bonding target portion is made rough while another part is kept smooth, creating local quality differences that control where plastic flow occurs. This allows the lower melting point material to flow into the rough portion while the higher melting point material flows into the smooth portion, achieving uniform plastic flow distribution across both materials.
Solution Approach 2:
The invention changes the surface roughness parameter of the bonding target portion to control plastic flow behavior. By making part of the surface rough and part smooth, the surface condition parameter is varied spatially to regulate where and how plastic flow occurs, enabling effective bonding of materials with different melting points.
2Length of moving object
If push-in depth increases to achieve longer bonding length, then bonding area increases, but undercut becomes larger due to excessive plastic flow of lower melting point material
Solution Approach 1:
The invention uses local quality differentiation on the bonding target portion surface, where rough and smooth areas are strategically positioned to control plastic flow distribution. This ensures that as push-in depth increases, the lower melting point material flows preferentially into the rough portion while the higher melting point material flows into the smooth portion, maintaining bonding precision and preventing undercut formation even at increased bonding lengths.
3Strength
If bonding current is applied to achieve plastic flow, then bonding strength increases, but spatter is generated due to excessive heat in lower melting point material
Solution Approach 1:
The invention applies local quality differentiation by creating rough and smooth regions on the bonding target portion. The rough portion receives the lower melting point material while the smooth portion receives the higher melting point material. This spatial separation of material flow paths distributes the heat generation from bonding current, preventing excessive heat concentration that would cause spatter in the lower melting point material while still achieving sufficient plastic flow for strong bonding.
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 enhances the effective bonding length and strength between metal materials with different melting points, allowing for longer and more reliable bonding without significant spatter generation, particularly achieving bonding lengths of 3 mm or more.
Implementation Method 1
one of the first and second bonding target members, whichever has a lower melting point, has a heat capacity increasing portion for increasing the heat capacity in the vicinity of the bonding target portion
Implementation Method 2
applying a bonding current to a bonding target portion between the first and second bonding target members with the pressing force being applied thereto
Implementation Method 3
the bonding target portion of the first bonding target member and the bonding target portion of the second bonding target member increase their bonding areas while undergoing plastic flow
Data Source
AI summary
A method for manufacturing a bonded article having long bonding length and high strength. A first bonding target member and a second bonding target member having a hole portion for receiving the first member are provided. Pressing force is applied between the two members with the first member received in the hole portion, and a current is applied to a bonding target portion between the two members with the pressing force applied. The two members are of materials with different melting points. One of the two members, having lower melting point, has a heat capacity increasing portion in the vicinity of the target portion. The one of the members has a taper face at the target portion, and the heat capacity increasing portion has a face extending from the taper face. The force applying step is performed with the other member positioned not to contact the heat capacity increasing portion.