cBN Sintered Compact Microstructure for Impact-Resistant Rock Drilling
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Solution Overview
Problem
Existing cBN sintered compacts used in drilling tools lack sufficient fatigue wear resistance, abrasive wear resistance, and resistance to damage from impacts and vibrations, which are critical for effective rock drilling.
Innovation Solution
A cBN sintered compact comprising cubic boron nitride grains and a binder phase with a Ti–Al alloy, Ti2CN, and TiB2, where the ratio of Ti2CN to Ti–Al alloy peak intensities and the aspect ratio and area rate of Ti and B element overlaps are optimized to enhance wear resistance and resistance to damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cBN sintered compacts are used for drilling tools, then they can perform basic cutting functions, but they exhibit insufficient fatigue wear resistance, abrasive wear resistance, and resistance to impact and vibration damage
Solution Approach 1:
The patent employs a composite binder phase consisting of Ti-Al alloy, Ti2CN, and TiB2 combined with cBN grains. This composite structure leverages the complementary properties of each component: Ti-Al alloy provides ductility and toughness, Ti2CN enhances wear resistance, and TiB2 contributes to hardiness and fracture resistance. The synergistic combination resolves the contradiction by achieving both improved reliability through fatigue wear resistance and enhanced strength against impact and vibration damage.
Solution Approach 2:
The patent optimizes specific parameters including the ratio of Ti2CN to Ti-Al alloy peak intensities (2.0-30.0) and the aspect ratio and area rate of Ti and B element overlaps (aspect ratio 1.7-6.5, area rate 0.025-0.120%). These parameter changes are critical for achieving the desired balance between fatigue wear resistance and resistance to impact damage, as they control the microstructure and bonding characteristics of the composite material.
2Reliability
If the binder phase contains Ti-Al alloy, Ti2CN, and TiB2 with optimized ratios, then fatigue wear resistance and abrasive wear resistance are enhanced, but the manufacturing complexity increases due to precise control requirements
Solution Approach 1:
The patent defines specific parameter ranges for the binder phase composition (Ti2CN/Ti-Al alloy intensity ratio of 2.0-30.0, aspect ratio of 1.7-6.5, area rate of 0.025-0.120%) that, when controlled within these ranges, ensure improved abrasive wear resistance. By establishing clear parameter boundaries, the patent simplifies the manufacturing process while maintaining high reliability, as these ranges provide a robust manufacturing window that accommodates normal process variations.
Data Source
AI summary
A cBN sintered compact comprises: cubic boron nitride grains and a binder phase, wherein1) the binder phase comprises a Ti—Al alloy containing at least one element selected from the group consisting of Si, Mg, and Zn, and further comprises Ti2CN and TiB2;2) the ratio ITi2CN/ITi-Al in XRD is 2.0 or more and 30.0 or less where ITi2CN represents the peak intensity of Ti2CN appearing at 2θ angle from 41.9° to 42.2° and ITi-Al represents the peak intensity of the Ti—Al alloy at 2θ angle from 39.0° to 39.3°;3) areas where Ti and B elements overlap have an average aspect ratio of 1.7 or more and 6.5 or less and an area rate of 0.025% or more and 0.120% or less, in a mapping image of the Ti and B elements by Auger electron spectroscopy.