Laminated Coated Cutting Tool for Wear and Fracture Resistance
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Solution Overview
Problem
Existing coated cutting tools face challenges in wear resistance and fracture resistance, particularly during high-speed and high-load processing of difficult-to-cut materials, leading to reduced tool life.
Innovation Solution
A coated cutting tool with a laminated structure comprising alternating layers of Ti(C x N 1-x ) and (Ti y Al 1-y )N, where x and y are within specific atomic ratios, and controlled thickness and grain size ranges, enhancing adhesion and compressive stress to improve wear and fracture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the coating layer has a large grain size (more than 200 nm), then wear resistance is improved, but fracture resistance deteriorates and sudden fractures occur
Solution Approach 1:
The coating layer is segmented into multiple sub-layers with different grain sizes: a first sub-layer with fine grains (30-100 nm) for fracture resistance, and a second sub-layer with coarse grains (100-500 nm) for wear resistance. This segmentation allows each sub-layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the coating layer are assigned different grain sizes and structures: the first sub-layer near the substrate has fine grains for adhesion and fracture resistance, while the second sub-layer at the surface has coarse grains for wear resistance. This local quality differentiation resolves the contradiction between wear resistance and fracture resistance.
2Manufacturing precision
If the coating layer has high interfacial consistency with small distortion, then manufacturing precision is improved, but hardness is insufficient and wear resistance deteriorates
Solution Approach 1:
The coating layer is designed as a composite structure with two distinct sub-layers: a first sub-layer with fine granular structure for adhesion and consistency, and a second sub-layer with coarse columnar structure for hardness and wear resistance. This composite approach allows both interfacial consistency and wear resistance to be achieved simultaneously.
Data Source
Figure 1
AI summary
Provided is a coated cutting tool having improved wear resistance and fracture resistance and a long tool life. The coated cutting tool includes a substrate, and a coating layer formed on a surface of the substrate. The coating layer has a laminated structure in which a first layer and a second layer are alternately laminated for one or more layers. The first layer is a compound layer having a composition represented by Ti(CxN1-x). The second layer is a compound layer having a composition represented by (TiyAl1-y)N. The laminated structure includes first to third laminated structures in this order from a substrate side to a surface side of the coating layer. An average thickness per layer of each of the first layer and the second layer in the first to third laminated structures is in a specific range. An average thickness of the first to third laminated structures is in a specific range.