AlTiN-Coated Cutting Edge Composition for Wear and Oxidation Resistance
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Solution Overview
Problem
Existing coated cutting tools face challenges in achieving a balance between toughness and hardness, particularly at the cutting edge, which affects their lifespan and resistance to wear and oxidation.
Innovation Solution
A coated tool with an AlTiN film having varying Al/(Al+Ti) ratios across different points near the cutting edge, with higher ratios further away enhancing hardness and oxidation resistance, while lower ratios near the edge improve toughness, achieved through a CVD process with specific gas composition and flow velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform AlTiN coating is applied to the cutting edge, then oxidation resistance is improved, but toughness at the cutting edge deteriorates
Solution Approach 1:
The coating composition is varied locally across the cutting edge region. The Al ratio is set to 0.6 or more at points 0.1mm or more from the cutting edge to ensure oxidation resistance, while allowing lower Al ratios near the cutting edge to maintain toughness. This local composition variation resolves the contradiction between oxidation resistance and toughness.
2Reliability
If the Al ratio is increased to improve oxidation resistance, then hardness is improved, but toughness deteriorates
Solution Approach 1:
Different Al ratios are applied to different regions: higher Al ratios (≥0.6) are used in regions 0.1mm or more from the cutting edge where oxidation resistance is critical, while lower Al ratios are permitted near the cutting edge where toughness is more important for withstanding mechanical stresses.
3Reliability
If a hard coating with high Al content is applied, then oxidation resistance is improved, but the coating becomes more brittle
Solution Approach 1:
The coating is designed with spatially varying composition: regions farther from the cutting edge (≥0.1mm) have high Al content (Al ratio ≥0.6) for oxidation resistance, while regions near the cutting edge have lower Al content to maintain ductility and prevent coating delamination under mechanical stress.
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 tool exhibits enhanced toughness, hardness, and oxidation resistance, leading to extended tool life with reduced crater and flank wear.
Implementation Method 1
achieved through a CVD process with specific gas composition and flow velocity
Data Source
AI summary
A coated tool in a non-limiting embodiment of the present disclosure includes a base and a coating film located on the base. The coated tool includes a first surface, a second surface adjacent to the first surface, and a cutting edge located on at least a part of a ridge part of the first surface and the second surface. The coating film includes an AlTiN film including Ti, Al and N. A first Al ratio and a second Al ratio are 0.7 or more. The first Al ratio is Al/(Al+Ti) at a point located 0.1 mm away from the cutting edge, and the second Al ratio is Al/(Al+Ti) at a point located 0.2 mm away from the cutting edge in the first surface. The second Al ratio is larger than the first Al ratio.