Bi-Copper Slide Member Bonding Interface Strength Control
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Solution Overview
Problem
The existing sliding members with copper alloy layers containing Bi phases at the bonding interface suffer from reduced strength, leading to fatigue cracks and early failure due to increased load conditions in engines or reduced bearing areas, resulting in local falling-off of the sliding layer.
Innovation Solution
A sliding member with a copper alloy layer bonded to a substrate, where the Bi phases are dispersed in a copper alloy matrix, with a volume ratio of Bi phases within 10 µm from the bonding interface not exceeding 3.0%, and a method involving unidirectional solidification of the copper alloy to control Bi phase distribution, enhancing the strength of the bonding interface region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Bi phases are dispersed in copper alloy matrix to improve seizure resistance, then conformability and foreign matter embedding performance are improved, but Bi phases accumulate at bonding interface during sintering, reducing strength of the region
Solution Approach 1:
The patent applies local quality by creating different Bi phase distributions in different regions of the copper alloy layer. Specifically, the volume ratio of Bi phases in the region within 10 µm from the bonding interface is controlled to be not more than 3.0%, while Bi phases are allowed to exist in the sliding surface region. This localized control of Bi phase concentration allows the bonding interface region to have high strength while the sliding surface region maintains good seizure resistance.
Solution Approach 2:
The patent employs preliminary action by controlling the solidification process to prevent Bi phase accumulation at the bonding interface before the sintering process completes. By adjusting the solidification speed during manufacturing, Bi phases are directed to precipitate in the sliding surface region rather than accumulating at the bonding interface, thereby preventing the formation of weak regions that would compromise strength.
2Ease of manufacture
If conventional sintering process is used to manufacture copper alloy sliding member, then manufacturing is simplified, but Bi phases accumulate at bonding interface causing early failure
Solution Approach 1:
The patent applies parameter changes by modifying the solidification speed parameter during the sintering process. By controlling the solidification speed to be within a specific range (0.1 to 10 °C/s), the patent prevents Bi phase accumulation at the bonding interface while maintaining the overall sintering process. This parameter control ensures that Bi phases precipitate in the sliding surface region rather than accumulating at the bonding interface, thereby improving durability without significantly complicating the manufacturing process.
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 controlled Bi phase distribution prevents fatigue crack progression to the bonding interface, thereby preventing early falling-off of the sliding layer, ensuring durability and reliability of the sliding member.
Implementation Method 1
the copper alloy layer is unidirectionally solidified by cooling a substrate from a surface opposite to a surface to be bonded to the copper alloy layer
Implementation Method 2
Bi is dispersed in a Cu alloy matrix to form soft Bi phases to improve seizure resistance
Data Source
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AI summary
The purpose of the present invention is to provide: a slide member in which the bonding strength between a Bi-containing copper alloy layer and a substrate is enhanced; and a method for manufacturing the slide member. The slide member according to the present invention has a substrate and a copper alloy layer. The copper alloy layer comprises a copper alloy containing 4.0-25.0 mass% of Bi and has a structure in which Bi phases are scattered in a copper alloy structure. The volume ratio of Bi phases in the region of the copper alloy layer extending 10 µm from the bonding interface with the substrate is not more than 2.0%. The slide member is manufactured by casting a molten copper alloy onto the substrate and causing the copper alloy to unidirectionally solidify.