WC Cemented Carbide Bonding via Ti Foil Diffusion
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Solution Overview
Problem
Conventional composite members and cutting tools experience insufficient bonding strength under heavy cutting conditions, leading to potential breakage at the bonding portion when subjected to high loads during high-feed rate and large depth of cut operations.
Innovation Solution
A composite member is formed by bonding WC-based cemented carbide members using a Ti foil bonding layer, with specific layer structures including TiC and TiCo phases, and a residual Ti layer, optimized for solid phase diffusion bonding to enhance adhesion and bonding strength, reducing internal residual stress and thermal expansion coefficient disparities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional bonding material is used to bond WC-based cemented carbide members, then the bonding process is simple, but the bonding strength is insufficient under heavy cutting conditions
Solution Approach 1:
The bonding layer is divided into multiple distinct layers (first bonding layer, second bonding layer, third bonding layer) with different compositions and functions. Each layer is optimized for specific purposes: the first layer provides initial bonding, the second layer enhances strength and reduces stress, and the third layer improves adhesion to the cemented carbide member.
Solution Approach 2:
The bonding layer uses composite material structures with multiple phases (metal phase, ceramic phase, carbide phase) distributed across different layers. This composite approach combines the advantages of different materials to achieve both high bonding strength and stress reduction capabilities.
2Strength
If a thick bonding layer is used to improve bonding strength, then adhesion is enhanced, but internal residual stress increases causing potential breakage
Solution Approach 1:
The thick bonding layer is segmented into multiple thinner sub-layers with different compositions. This segmentation allows each sub-layer to have controlled thickness that minimizes residual stress while collectively providing the needed bonding strength through their combined structure.
Solution Approach 2:
The composition parameters (phase distribution, material ratios) are changed across different layers to optimize both strength and stress characteristics. The metal phase content, ceramic phase content, and carbide phase content are specifically adjusted in each layer to balance bonding strength and residual stress.
3Strength
If a simple single-layer bonding structure is used, then manufacturing is easier, but bonding strength under high load is insufficient
Solution Approach 1:
The bonding process is segmented into multiple stages corresponding to the formation of different layers. Each layer can be formed through controlled application and processing steps, making the complex multi-layer structure manufacturable through systematic process control.
Solution Approach 2:
Processing parameters (temperature, pressure, time) are changed in a controlled sequence to form each layer with specific characteristics. This parameter control enables the fabrication of complex multi-layer structures while maintaining manufacturing feasibility through standardized process steps.
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 composite member exhibits enhanced bonding strength and prevents breakage at the bonding portion, ensuring excellent cutting performance for long-term usage even under high load conditions, such as heavy cutting of steel or cast iron.
Implementation Method 1
bonding is performed between the first bonded material and the second bonded material via a bonding material 2 which does not generate a liquid phase when a temperature is less than 1000° C., by electrically heating while applying a pressure
Data Source
AI summary
A composite member in which WC-based cemented carbide members are bonded to each other via a bonding layer formed by solid phase diffusion bonding of a bonding member made of a Ti foil. The bonding layer is constituted by first layers adjacent to the WC-based cemented carbide members and made of a TiC phase and a metal W phase in which an average area ratio of the TiC phase is 40 to 60%. The bonding layer also includes second layers adjacent to the first layers and made of a TiCo phase and a metal Ti phase in which an average area ratio of the TiCo phase is 50 to 95%, and a residual Ti layer.