Semi-Compliant Sintered Fasteners for Thermal Expansion Mismatch
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Solution Overview
Problem
Conventional fastening techniques fail to effectively join substrates with different coefficients of thermal expansion, leading to heat transfer issues and mechanical failure due to large expansion differences, especially in high-temperature applications.
Innovation Solution
Sinterable fastener precursors are used, which are injected into bores and sintered to form mechanical fasteners that shrink and interlock with substrate features, providing compliance and heat resistance while maintaining a connection between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal fasteners are used to join substrates, then mechanical strength and compliance are improved, but heat transfer between substrates increases
Solution Approach 1:
The patent changes the material parameter from metal to ceramic, which fundamentally alters the thermal conductivity while maintaining mechanical fastening capability. The ceramic material provides high-temperature stability and low thermal conductivity, resolving the contradiction between mechanical strength and heat transfer prevention.
Solution Approach 2:
The fastener uses a composite structure combining ceramic matrix with reinforcement elements (such as fibers or particles). This composite approach maintains the low thermal conductivity of ceramic while improving mechanical strength and fracture toughness, allowing the fastener to withstand thermal expansion differences without becoming a heat bridge.
2Object-affected harmful factors
If ceramic fasteners are used to reduce heat transfer, then heat resistance is improved, but compliance and mechanical reliability worsen due to thread failure under thermal expansion stress
Solution Approach 1:
The ceramic matrix composite structure incorporates reinforcement phases (fibers, particles, or whiskers) that bridge cracks and prevent catastrophic failure. This allows the ceramic fastener to maintain reliability under thermal cycling and expansion stresses while preserving the low thermal conductivity needed for heat isolation.
Solution Approach 2:
The fastener design incorporates localized features such as compliant threads, flexible engagement zones, or stress-distributing geometries in specific regions. These local modifications allow the ceramic material to accommodate differential thermal expansion without compromising overall structural integrity or creating failure points.
3Ease of manufacture
If conventional joining techniques are used, then manufacturing simplicity is maintained, but the ability to accommodate thermal expansion differences is lost
Solution Approach 1:
The invention changes the material parameter from metal to ceramic, which fundamentally alters the thermal and mechanical properties. This material substitution enables the fastener to accommodate thermal expansion differences while maintaining a relatively simple manufacturing process similar to conventional fastener production.
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 sintered fasteners effectively reduce heat transfer and maintain a strong, compliant connection across substrates with different thermal expansion coefficients, enhancing the durability and reliability of assemblies in high-temperature environments.
Implementation Method 1
sintering the fastener precursor in the bore. The fastener precursor densifies and shrinks in at least one dimension to mechanically interlock with a contour in the bore
Implementation Method 2
Ceramic fasteners reduce heat transfer, but are less compliant than metal joints
Data Source
AI summary
A method for connecting or joining a first substrate and a second substrate across an interface between the first substrate and the second substrate. The method includes disposing a fastener precursor in the bore and sintering the fastener precursor in the bore. The fastener precursor densifies and shrinks in at least one dimension to mechanically interlock with a contour in the bore and form a mechanical fastener in the bore, and the mechanical fastener forms an interlock between the first substrate and the second substrate.