Titanium Carbonitride Hard Material for Tougher Cutting Tools
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Solution Overview
Problem
Cutting tools face challenges with fracture toughness and thermal conductivity due to the use of titanium carbonitride powders with small average grain sizes, leading to decreased performance under severe cutting conditions.
Innovation Solution
A hard material with a first hard phase containing titanium carbonitride and a binder phase with an iron group element, where the grain size D50 is 1.0 μm or more and the average aspect ratio of first hard phase particles is 2.0 or less, improving fracture toughness and thermal conductivity by inhibiting crack propagation and reducing phonon scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If titanium carbonitride powder with small average grain size is used, then hardness is improved, but fracture toughness deteriorates
Solution Approach 1:
The invention changes the grain size parameter of titanium carbonitride powder from small (conventional) to large (D50: 1.0 μm or more, preferably 1.5 μm to 5.0 μm). This parameter change resolves the contradiction by improving fracture toughness while maintaining acceptable hardness through controlled grain growth that prevents excessive coarsening.
Solution Approach 2:
The invention creates local quality differences by controlling the grain size distribution of titanium carbonitride particles. By ensuring D50 is 1.0 μm or more while maintaining a controlled distribution, the material achieves local regions with optimal grain sizes that balance hardness and fracture toughness, preventing both overly fine and overly coarse structures.
2Manufacturing precision
If titanium carbonitride powder with small average grain size is used, then manufacturing precision is improved, but thermal conductivity deteriorates
Solution Approach 1:
The invention changes the thermal conductivity parameter by controlling grain size to D50 of 1.0 μm or more. This reduces phonon scattering at grain boundaries, thereby improving thermal conductivity while maintaining manufacturing precision through controlled grain size distribution during the sintering process.
3Reliability
If grain size is increased to improve fracture toughness, then hardness deteriorates
Solution Approach 1:
The invention optimizes the grain size parameter to a specific range (D50: 1.0 μm or more, preferably 1.5 μm to 5.0 μm) rather than simply increasing it. This controlled parameter change achieves sufficient fracture toughness improvement while preventing excessive grain coarsening that would cause hardness deterioration, thus resolving the contradiction.
Solution Approach 2:
The invention applies partial grain growth by controlling D50 to be 1.0 μm or more without allowing uncontrolled grain coarsening. This partial action approach achieves the necessary fracture toughness improvement while maintaining hardness by preventing excessive grain size increase.
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 hard material exhibits superior fracture toughness and thermal conductivity, enabling machining under more severe conditions and extending tool life, while maintaining hardness and wear resistance.
Implementation Method 1
improving fracture toughness and thermal conductivity by inhibiting crack propagation
Implementation Method 2
improving fracture toughness and thermal conductivity by inhibiting crack propagation and reducing phonon scattering
Data Source
AI summary
A hard material includes a first hard phase containing titanium carbonitride as a major constituent and a binder phase containing an iron group element as a major constituent. In any surface or cross-section of the hard material, the grain size D50 at a cumulative percentage of 50% of a grain size distribution by area of the first hard phase is 1.0 μm or more, and the average aspect ratio of first hard phase particles having grain sizes larger than or equal to D50 is 2.0 or less.