Bonding Metal Inserts to Carbon-Carbon Composites via Combustion Synthesis
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Solution Overview
Problem
The use of metal inserts in carbon-carbon composite brake discs for aircraft requires drilling holes for riveting, increasing manufacturing time, cost, and weight, and is prone to rivet failure.
Innovation Solution
A reactive mixture of fine metal and carbon powders is applied between the carbon-carbon composite piece and metal insert, compressed, and ignited with an electric current to form molten metal carbide ceramic, bonding the components without rivets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal inserts are riveted to carbon-carbon composite brake discs, then metal-to-metal interface is provided to reduce wear and chipping, but manufacturing time, cost, and weight increase due to drilling holes and installing rivets
Solution Approach 1:
The invention extracts and eliminates the rivets and drilling operations from the manufacturing process. Instead of using mechanical fasteners, the patent applies a metallic coating directly to the carbon-carbon composite brake disc surface through thermal spray or plasma spray processes, thereby providing the metal-to-metal interface without the need for holes or rivets, reducing manufacturing time and complexity while maintaining wear resistance
Solution Approach 2:
The invention replaces the mechanical fastening system (drilling holes and installing rivets) with a thermal deposition system. The metallic coating is applied through thermal spray or plasma spray processes that deposit molten or semi-molten metal particles onto the brake disc surface, creating a bonded metallic layer that provides the required metal-to-metal interface without mechanical fasteners
2Reliability
If metal inserts are riveted to carbon-carbon composite brake discs, then metal-to-metal interface is provided to reduce wear and chipping, but manufacturing cost increases due to expensive rivets and labor-intensive installation
Solution Approach 1:
The invention extracts and eliminates the expensive rivets and labor-intensive drilling operations from the manufacturing process. The metallic coating is applied directly to the brake disc surface through automated thermal spray or plasma spray processes, eliminating the need for costly mechanical fasteners and reducing labor requirements while maintaining the metal-to-metal interface for wear resistance
Solution Approach 2:
The invention replaces the mechanical fastening system with a thermal deposition system that can be automated. The thermal spray or plasma spray processes allow for continuous coating application without the need for hole drilling and rivet installation, significantly reducing labor costs and manufacturing complexity while providing the required wear-resistant metallic interface
3Reliability
If metal inserts are riveted to carbon-carbon composite brake discs, then metal-to-metal interface is provided to reduce wear and chipping, but brake disc weight increases due to additional rivets
Solution Approach 1:
The invention extracts and eliminates the additional weight of rivets from the brake disc assembly. By applying a metallic coating directly to the carbon-carbon composite surface through thermal spray or plasma spray processes, the method provides the necessary metal-to-metal interface for wear resistance without the added weight of mechanical fasteners, resulting in a lighter overall brake disc
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
This method results in a lighter, stronger, and cheaper brake disc with reduced manufacturing time and labor, maintaining thermal properties and durability.
Implementation Method 1
an electric current passes between the carbon-carbon composite piece and the metal insert heating and igniting the powder mixture
Implementation Method 2
The resulting high temperature combustion reaction creates molten metal carbide ceramic
Implementation Method 3
The molten ceramic quickly freezes, bonding the carbon-carbon composite piece and the metal insert
Data Source
AI summary
Method of joining a carbon-carbon composite piece 30 together with a metal insert 20, e.g. in the manufacture of aircraft brake discs 10. The method includes the steps of: providing a carbon-carbon composite piece 30 and a metal insert 20, wherein the metal insert 20 has a surface that is complementary to a surface of said carbon-carbon composite piece 30; providing a layer of a mixture of titanium powder and carbon powder on the first complementary mating surface; arranging the powder layer such that a second complementary mating surface is matched to the complementary mating surface, thereby forming a construct of the carbon-carbon composite piece 30, the powder layer, and the metal insert 20; placing the construct into a press and applying pressure to the construct to press together the carbon-carbon composite piece and the metal insert joined at their complementary surfaces; and applying an electrical current to the powder in the construct to initiate a metal-carbon reaction, thereby bonding the carbon-carbon composite piece 30 together the metal insert 20. The titanium powder particles may be from 25 to 100 microns in diameter, and the carbon powder (e.g., graphite particles) may be 0.1 to 1 microns in diameter.