CBN Sintered Body Binder Composition for Tougher Cutting Tools
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Solution Overview
Problem
Existing cBN sintered bodies require further improvements in toughness to accommodate increased cutting speeds.
Innovation Solution
A cBN-based ultra-high pressure sintered body with a specific composition and distribution of metal boride particles in the binder phase, including Nb, Ta, Cr, Mo, and W, promotes bonding between cBN particles and the binder phase, enhancing toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal boride particles are dispersed in the binder phase, then the reaction between cBN particles and the binder phase is promoted and bonding is strengthened, but the device complexity increases due to the need to control particle size, composition, and distribution
Solution Approach 1:
The invention optimizes specific parameters of metal boride particles including size (50-500 nm), composition ratios (Ti: 10-50 mass%, Nb: 30-70 mass%, Ta: 10-50 mass%), and volume percentage in binder phase (5-30 vol%). By precisely controlling these parameters, the invention achieves improved toughness while managing the complexity through defined ranges rather than unlimited variations.
Solution Approach 2:
The invention uses composite metal boride particles containing multiple metal elements (Ti, Nb, Ta) dispersed in the binder phase. This composite approach enhances the reaction promotion effect and bonding strength between cBN particles and binder phase, thereby improving toughness. The composite structure allows synergistic effects of different metal borides to work together.
2Strength
If fine metal boride particles are dispersed in the binder phase, then toughness is improved by dispersion strengthening effect, but manufacturing precision requirements increase for achieving uniform distribution
Solution Approach 1:
The invention specifies a particle size range of 50-500 nm for metal boride particles, which is fine enough to provide dispersion strengthening effect but controlled enough to achieve uniform distribution. The size parameter is optimized to balance the strengthening effect with manufacturability and distribution uniformity.
Solution Approach 2:
The invention ensures uniform local distribution of metal boride particles throughout the binder phase by controlling their dispersion. This local uniformity is achieved by optimizing the particle size and using appropriate mixing and sintering processes, ensuring that every region of the sintered body benefits from the dispersion strengthening effect.
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 cBN sintered body exhibits improved toughness, chipping resistance, and extended tool life, making it suitable for cutting tools with reduced defects and increased durability.
Implementation Method 1
a fine Ti boride phase having an average particle diameter of 50 to 500 nm and a fine W boride phase having an average particle diameter of 50 to 500 nm are dispersed and distributed in a binder phase, and toughness is improved by a dispersion strengthening effect of the binder phase
Implementation Method 2
the reaction between the cBN particles and the binder phase in the sintered body is promoted, the bonding is strengthened, and thus the toughness of the cBN sintered body is improved
Data Source
AI summary
A cBN-based ultra-high pressure sintered body contains cBN particles and a binder phase. The binder phase contains at least one of a nitride or oxide of Al or a nitride, carbide, or carbonitride of Ti, and a metal boride having an average particle diameter of 20 to 300 nm is dispersed in an amount of 0.1 to 5.0 vol % in the binder phase. The metal boride includes a metal boride (B) containing at least one of Nb, Ta, Cr, Mo, and W as a metal component and containing no Ti and a metal boride (A) containing only Ti as a metal component. In a case where a ratio (vol %) of the metal boride (A) in the metal boride is represented by Va and a ratio (vol %) of the metal boride (B) is represented by Vb, a ratio of Vb/Va is 0.1 to 1.0.