CMC Reactive Infiltration Using Silicide-Forming Binary Alloys
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Solution Overview
Problem
The high melting temperature of silicon limits the operational temperature of silicon melt-infiltrated ceramic matrix composite (CMC) components, and higher temperature metals used as infiltrants can damage the fibers during infiltration.
Innovation Solution
The use of eutectic and metal-rich binary alloys with melting points between 1,250° C. to 1,650° C., comprising constituents like zirconium, hafnium, tungsten, tantalum, molybdenum, niobium, and iridium, which react with carbon sources to form silicides and carbides, minimizing residual silicon and protecting the fibers during reactive infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silicon is used as the infiltrant material, then the CMC component can be fabricated, but the operational temperature is limited to below silicon's melting point of 1410°C
Solution Approach 1:
The invention changes the chemical composition parameters of the infiltrant material from pure silicon to binary alloys containing silicon with metals such as zirconium, hafnium, tungsten, tantalum, molybdenum, niobium, or iridium. This compositional parameter change enables the material to form high-temperature silicide compounds (e.g., ZrSi2, HfSi2) that maintain structural integrity at temperatures above 1410°C while still allowing infiltration at lower temperatures
Solution Approach 2:
The invention uses composite material formation by reacting the silicon-based alloy infiltrant with carbon source material to create a composite matrix containing silicides and carbides. This composite structure combines the benefits of high-temperature stability from silicides with the protective properties of carbides, enabling operational temperatures exceeding 1410°C while maintaining fiber protection
2Temperature
If higher temperature metals are used as infiltrants to increase operational temperature, then the melting point increases, but the fibers are damaged during infiltration
Solution Approach 1:
The invention adjusts the melting point parameter of the infiltrant material by selecting specific binary alloy compositions. The alloys are designed to have melting points between 1250°C and 1650°C, which is high enough to enable subsequent high-temperature operation but low enough to prevent fiber damage during the infiltration process. This precise parameter control resolves the contradiction between achieving high melting point and avoiding fiber damage
Solution Approach 2:
The silicon-based binary alloy acts as an intermediary material that enables the transition from low-temperature infiltration to high-temperature operation. The alloy composition serves as a mediator between the infiltrant and the carbon source material, facilitating controlled reaction to form protective silicide and carbide phases that protect fibers while enabling high-temperature performance
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 solution allows for CMC materials to withstand higher temperatures without fiber damage, ensuring a robust and durable matrix with minimal residual silicon, enhancing the material's heat tolerance and strength.
Implementation Method 1
reacting either the at least one eutectic alloy constituent or the at least one metal-rich alloy constituent with the carbon source material; forming at least one matrix material within, around and in contact with the at least one ceramic fiber or the at least one ceramic fiber tow, the at least one matrix material comprising at least one eutectic alloy, at least one metal-rich alloy, and combinations thereof; wherein the at least one matrix material comprises at least one silicide, at least one carbide, residual free silicon, or combinations thereof
Data Source
AI summary
A gas turbine engine component includes a component including at least one ceramic matrix composite material, the at least one ceramic matrix composite material further includes a ceramic fiber reinforcement containing at least one ceramic fiber or at least one ceramic fiber tow; and a matrix material disposed around and in contact with the at least one ceramic fiber or the at least one ceramic fiber tow; the matrix material contains at least one eutectic alloy, at least one metal-rich alloy, or combinations thereof; either the at least one eutectic alloy or the at least one metal-rich alloy includes silicon and at least one of the following alloy constituents: zirconium, hafnium, tungsten, tantalum, molybdenum, niobium, and iridium; and, either the at least one eutectic alloy or the at least one metal-rich alloy exhibits and possesses a melting point range of approximately 1,250° C. to approximately 1,650° C.