Ceramic Matrix Composite Braze Joint via Localized Heating
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Solution Overview
Problem
Joining ceramic or ceramic matrix composite components is challenging due to high melting points, decomposition risks, and thermal shock susceptibility, with existing methods like cements being brittle and fasteners introducing cracks.
Innovation Solution
A method involving positioning ceramic or CMC parts adjacent to each other, delivering a solid braze material comprising a filler and metal alloy, and locally heating it to react and form a joint, using techniques like laser or plasma arc heating to join the parts without significant thermal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cements are used to join ceramic or CMC parts, then the parts can be joined together, but the joint is prone to brittle fracture under tension or flexure
Solution Approach 1:
The invention changes the material parameters of the joining agent by using a metal or alloy with melting point lower than the ceramic or CMC, transforming it from a brittle cement into a ductile braze material that can absorb stress and prevent brittle fracture while maintaining ease of application
Solution Approach 2:
The invention creates a composite joining system where a metal or alloy braze material is combined with filler material to form a eutectic composition, resulting in a joint that exhibits both ease of manufacture and high strength by leveraging the complementary properties of the constituent materials
2Ease of operation
If fasteners such as screws or bolts are used to join ceramics or CMCs, then the parts can be mechanically connected, but holes must be formed which introduce cracks and stress concentrators
Solution Approach 1:
The invention extracts and eliminates the hole-forming step entirely by using a braze material that flows into and bonds the joint surfaces directly, removing the source of cracks and stress concentrators while maintaining ease of assembly through a straightforward joining process
Solution Approach 2:
The braze material serves as an intermediary substance that fills the joint region between ceramic or CMC parts, creating a strong bond without requiring mechanical fasteners or hole formation, thereby preserving structural integrity while enabling easy assembly
3Strength
If high temperature joining is used to join ceramic or CMC parts, then strong joints can be formed, but thermal shock susceptibility increases due to the inherent brittleness of ceramics
Solution Approach 1:
The invention changes the temperature parameter profile by using a braze material with lower melting point than the ceramic or CMC, enabling joining at reduced temperatures that avoid excessive thermal gradients and minimize thermal shock susceptibility while still forming strong joints
Solution Approach 2:
The invention applies local quality by concentrating the heat input specifically in the joint region using localized heating, allowing the bulk of the ceramic or CMC parts to remain at lower temperatures, thereby reducing overall thermal stress and thermal shock susceptibility while achieving strong local bonding
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
Enables the joining of complex geometry components with improved high-temperature capability and reduced thermal shock risk, producing joints with similar thermophysical and mechanical properties to the parent materials.
Implementation Method 1
a constituent of the filler material reacts with a constituent of the molten metal or alloy to join the first part and the second part
Implementation Method 2
locally heating, using at least one of a laser or a plasma arc source, the joint region
Implementation Method 3
locally heating, using at least one of a laser or a plasma arc source, the joint region
Implementation Method 4
cooling the joint region to result in the first and second parts being joined
Data Source
AI summary
In some examples, a technique may include positioning a first part comprising a ceramic or ceramic matrix composite and a second part comprising a ceramic or a CMC adjacent to each other to define a joint region at the interface of the first part and the second part. In some examples, the joint region may be heated using at least one of a laser or a plasma arc source to heat the joint region to an elevated temperature. The first and second parts may be pressed together and cooled to join the first and second parts at the joint region. In other examples, a solid braze material including a filler material and a metal or alloy may be delivered to the joint region and locally heated to cause a constituent of the filler material and a constituent of the metal or alloy to react. When reacted, the constituents may form a solid material, which may join the first and second parts.