Coated Cemented Carbide Binder Composition for Fracture and Heat Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cutting tools used for difficult-to-cut materials like titanium and heat-resistant alloys experience premature fracture due to high heat generation, welding of cutting chips, and diffusion wear, leading to short tool life and reduced strength at the cutting edge.
Innovation Solution
A coated cemented carbide composition with a specific ratio of tungsten carbide as the hard phase and a binder phase containing Co and platinum group elements, along with a controlled hexagonal structure, enhances fracture resistance and heat resistance, and a coating layer improves adhesiveness and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Co in the binder phase is partially transformed into a hexagonal close-packed structure by air blasting treatment to improve fracture resistance, then compression stress is introduced and fracture resistance is improved, but heat resistance deteriorates because the melting point of Co is low and diffusion wear progresses
Solution Approach 1:
The invention changes the chemical composition parameters of the binder phase by adding platinum group elements (Ru, Rh, Pd, Os, Ir, or Pt) to Co, transforming the binder phase from pure Co to a Co-based alloy. This parameter change enables the material to maintain both the compression stress benefits of hexagonal Co structure and the high temperature stability of platinum group elements, resolving the contradiction between fracture resistance and heat resistance
Solution Approach 2:
The invention creates a composite binder phase system combining Co with platinum group elements. The Co component provides the necessary compression stress through hexagonal structure transformation, while the platinum group elements contribute high temperature stability and resistance to diffusion wear. This composite approach allows simultaneous achievement of improved fracture resistance and maintained heat resistance
2Strength
If a coating layer is formed onto the surface of the cemented carbide to improve wear resistance, then wear resistance is improved, but adhesiveness of the coating layer deteriorates
Solution Approach 1:
The invention applies local quality modification by forming an adhesive layer with specific composition (containing Co and platinum group elements matching the binder phase) at the interface between the coating and substrate. This localized composition design ensures strong metallurgical bonding at the interface while the outer coating layer maintains its wear-resistant properties, thus resolving the contradiction between wear resistance and adhesiveness
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 coated cemented carbide exhibits improved fracture resistance and extended tool life, particularly in cutting difficult-to-cut materials, making it suitable for high-performance cutting tools.
Implementation Method 1
by reacting a cemented carbide and a work piece material, diffusion wear proceeds
Implementation Method 2
adhesiveness of the coating layer is improved by devising a coating layer formed onto the surface of the cemented carbide
Data Source
AI summary
This is to provide a cemented carbide and a coated cemented carbide having excellent fracture resistance when they are used as cutting tools. The cemented carbide comprises 85% by mass or more and 97% by mass or less of a hard phase and 3% by mass or more and 15% by mass or less of a binder phase. A main component of the hard phase is tungsten carbide. The binder phase contains Co, and at least one kind of a platinum group element selected from the group consisting of Ru, Rh, Pd, Os, Ir and Pt. In the peaks of the Co obtained by an X-ray diffraction analysis, an intensity ICoc of a (200) plane of cubic Co and an intensity ICoh of a (101) plane of hexagonal Co satisfy a relation of the following formula. 0.1≦ICoh/ICoh+ICoc≦0.6.