Cutting Tool Coating with Localized Al and Si Ratios
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Solution Overview
Problem
Current cutting tools with Ti, Al, and Si coating layers lack sufficient wear and fracture resistance, particularly on the rake and flank faces, and require further improvements in oxidation resistance and chipping resistance.
Innovation Solution
A cutting tool with a coating layer composition of Ti 1-a-b-c Al a Si b M c (C 1-x N x) on the rake and flank faces, where M is selected from Y, Group-4, and Group-6 metals, with specific atomic percentage ranges and Si/Al ratios, enhancing oxidation resistance and chipping resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a coating layer containing Ti, Al, and Si is formed, then oxidation resistance is improved, but wear resistance and fracture resistance are insufficient
Solution Approach 1:
The coating layer has different compositions on the rake face and flank face. The rake face has higher Al content for oxidation resistance, while the flank face has higher Si content for wear and fracture resistance, allowing each surface to be optimized for its specific functional requirements
Solution Approach 2:
The invention changes the compositional parameters of the coating layer by controlling the atomic percentages of Ti, Al, and Si within specific ranges (0.3 ≤ a ≤ 0.7 for Al, 0.01 ≤ b ≤ 0.2 for Si) to achieve the desired balance between oxidation resistance and mechanical properties
2Object-affected harmful factors
If the Ti proportion is increased to improve hardness, then oxidation resistance improves, but chipping resistance deteriorates
Solution Approach 1:
Different regions of the coating have different Ti proportions optimized for their specific functions. The rake face has lower Ti content to maintain oxidation resistance, while the flank face has higher Ti content to enhance chipping resistance through increased hardness
Solution Approach 2:
The coating layer is a composite material combining Ti, Al, and Si in specific proportions, where each element contributes different properties: Ti for hardness and chipping resistance, Al for oxidation resistance, and Si for wear resistance, creating a synergistic effect
3Object-affected harmful factors
If the coating layer composition is optimized for oxidation resistance, then rake face performance improves, but flank face chipping resistance deteriorates
Solution Approach 1:
The coating layer exhibits spatial variation in composition, with the rake face having higher Al content for oxidation resistance and the flank face having higher Si and Ti content for chipping resistance, allowing each surface to be locally optimized for its specific functional requirements
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
AI summary
Disclosed is a cutting tool including a coating layer on a substrate that includes a rake face and a flank face. The a coating layer includes Ti1-a-b-cAlaSibMc(C1-xNx) where M is at least one selected from the group consisting of Y, Group-4, 5, and 6 metals, excluding Ti. The following equations are satisfied for the coating layer at the rake face: 0.3 ≤ a ≤ 0.7; 0.01 ≤ b ≤ 0.2; 0 ≤ c ≤ 0.3; and 0 < x ≤ 1, and also following equations are satisfied: 1.05 ≤ Sif/Sir ≤ 3.2; and 1.03 ≤ Alr/Alf ≤ 1.6, where Sir and Sif are proportions of Si in the coating layer at the rake face and at the flank face, respectively, and Alr and Alf are proportions of Al in the coating layer at the rake face and at the flank face, respectively.