Composite Cutting Tool Bonding Layer Design
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Solution Overview
Problem
Existing composite cutting tools with cBN sintered materials and WC-based cemented carbide face issues with bonding strength, particularly under heavy cutting conditions, leading to breakage and limited compatibility with materials like steel and cast iron.
Innovation Solution
The formation of a TiC-based layer, a Ti-Ni enriched layer, and an intermittent net structure, along with a needle structure containing Ti, B, and N, enhances the bonding strength between the cBN sintered material and the WC-based cemented carbide, using Ti-Ni laminated foils or mixed powders under ultra-high pressure and high temperature sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cBN sintered material is used in the cutting edge part, then productivity and service life are improved, but bonding strength deteriorates under heavy cutting conditions
Solution Approach 1:
The invention uses a composite bonding part containing both Ti and Ni (with Ni at 10-70 atomic%) bonded to cBN sintered material. This composite structure combines the high bonding strength of Ti with the ductility and toughness of Ni, creating a bonding layer that maintains strong adhesion while resisting crack propagation under heavy cutting loads, thereby preventing breakage while maintaining productivity.
Solution Approach 2:
The invention optimizes the Ni content parameter within a specific range (10-70 atomic%) to balance bonding strength and crack resistance. By controlling the composition parameters of the bonding part, the material achieves both strong bonding to cBN and sufficient toughness to prevent breakage under heavy cutting conditions, resolving the contradiction between productivity and bonding strength.
2Strength
If Ti is used in the bonding part to improve bonding strength, then bonding strength is improved, but crack occurrence increases
Solution Approach 1:
The invention creates a bonding part with non-uniform Ni distribution, concentrating Ni (10-70 atomic%) in specific regions where crack initiation is most likely. This local enrichment of Ni provides crack-arresting capability at critical locations while maintaining Ti-based strong bonding in other regions, thus improving reliability without sacrificing bonding strength.
Solution Approach 2:
Ni acts as an intermediary element between Ti and cBN sintered material. It mediates the stress distribution and crack propagation, absorbing energy and preventing crack development while Ti provides the primary bonding strength. This intermediary role of Ni resolves the contradiction by decoupling the bonding function (Ti) from the crack-resistance function (Ni).
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 significantly improves bonding strength, preventing breakage and enabling excellent cutting performance even under high-load conditions, such as cutting steel or cast iron, while maintaining tool integrity and efficiency.
Implementation Method 1
using Ti-Ni laminated foils or mixed powders under ultra-high pressure and high temperature sintering
Implementation Method 2
under ultra-high pressure and high temperature sintering
Data Source
Figure 1~2
Figure 3~4
AI summary
A composite part (1) including: a cutting edge part (2) made of cubic boron nitride sintered material or WC-based cemented carbide; a cutting tool body (4) made of WC-based cemented carbide; and a bonding part (3) provided between the cutting edge part and the cutting tool body and bonding thereof, is provided. A primarily TiC layer (9) containing 50 area% or more of TiC is formed in an interface between the cemented carbide and the bonding part, the primarily TiC layer (9) having an average layer thickness of 0.5 µm to 3 µm; and a Ti-Ni enriched layer (8) containing each of Ti and Ni at 30 atomic% or more is formed adjacent to the primarily TiC layer (9), the Ti-Ni enriched layer (8) having an average layer thickness of 0.3 µm to 3 µm. An intermittent net structure (7) containing each of Ti, Ni and C at 10 atomic% or more is formed adjacent to the primarily TiC layer (9), a straight line overlapping with a major axis of each of crystal grains containing each of Ti, Ni, and C at 10 atomic% or more intersecting 3 or more other crystal grains.