Polycrystalline Diamond Structure with Alternating Stress Regions
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Solution Overview
Problem
Polycrystalline diamond (PCD) tool inserts used in drilling and rock degradation lack enhanced fracture resistance, despite their high abrasion resistance, which limits their effectiveness in demanding applications.
Innovation Solution
A PCD structure is created with alternating regions of compressive and tensile residual stress states, formed by intergrowth of diamond grains of different grades, bonded to a cemented carbide support body, and processed under ultra-high pressure and temperature to achieve enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PCD material is used for tool inserts, then abrasion resistance is improved, but fracture resistance deteriorates
Solution Approach 1:
The patent applies local quality by creating regions with different PCD grades having distinct mechanical properties. Specifically, it forms a first region with a first PCD grade and a second region with a second PCD grade, where each region's grade is selected to provide optimal local performance. The first region may have higher hardness while the second region has higher toughness, allowing each area to be optimized for its specific functional requirements.
Solution Approach 2:
The patent employs composite materials by combining different PCD grades in a single tool insert structure. The composite consists of multiple regions with different diamond grain sizes, catalyst content, and sintering characteristics, creating a material system that integrates both high abrasion resistance and enhanced fracture resistance through the synergistic properties of its constituent grades.
2Reliability
If different PCD grades are combined in alternating layers, then fracture resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the PCD tool insert into multiple alternating layers or regions, each comprising a different PCD grade. This segmentation allows the material to be constructed from discrete, manufacturable layers that can be independently optimized. The alternating layer structure creates a laminated composite that gains fracture resistance through the arrangement of different grades while maintaining manufacturability through systematic layering.
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 resulting PCD structure exhibits improved fracture resistance and wear performance, extending the tool's lifespan and cutting efficiency in harsh environments like drilling into earth materials.
Implementation Method 1
PCD material comprises a mass of substantially inter-grown diamond grains and interstices between the diamond grains. PCD may be made by subjecting an aggregated mass of diamond grains to an ultra-high pressure and temperature in the presence of a sintering aid such as cobalt, which may promote the inter-growth of diamond grains.
Implementation Method 2
PCD may be made by subjecting an aggregated mass of diamond grains to an ultra-high pressure and temperature
Implementation Method 3
PCD may be made by subjecting an aggregated mass of diamond grains to an ultra-high pressure and temperature in the presence of a sintering aid such as cobalt, which may promote the inter-growth of diamond grains. The sintering aid may also be referred to as a catalyst material for diamond.
Implementation Method 4
a PCD structure comprising a first region in a state of residual compressive stress, and a second region adjacent the first region, the second region being in a state of residual tensile stress
Data Source
AI summary
A PCD structure comprising a first region, in a state of residual compressive stress, and a second region in a state of residual tensile stress adjacent the first region; the first and second regions each formed of respective PCD grades and directly bonded to each other by intergrowth of diamond grains, the PCD grades having transverse rupture strength (TRS) of at least 1,200 MPa. A third region in a state of residual compressive stress may also be provided such that the second region is disposed between the first and third regions and is bonded to the first and third regions by intergrowth of diamond grains.