Silicide-Based Composite Material for High-Temperature Gas Turbines
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Solution Overview
Problem
Nickel-base superalloys used in gas turbine applications have limitations such as low melting point and inadequate fracture toughness, which restrict their mechanical and thermal performance at high temperatures, necessitating the development of materials with improved thermal fatigue, oxidation resistance, strength-to-weight ratio, and creep properties.
Innovation Solution
A silicide-based composite material comprising Mo, B, W, Nb, Ta, Ti, Cr, Co, Si3N4, and oxide particles, produced through a process involving powder blending and selective melting, which enhances mechanical and thermal properties by controlling microstructure and overcoming sintering limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If nickel-base superalloys are used for gas turbine applications, then good mechanical properties at high temperature are achieved, but the melting point limits the operating temperature to below 1150°C
Solution Approach 1:
The patent develops composite materials comprising structural ceramics (SiC, Si3N4) and structural silicides (MoSi2) that combine the high-temperature stability of ceramics with the ductility and toughness of silicides, enabling operation above 1200°C while maintaining mechanical strength
2Strength
If structural ceramics such as SiC and Si3N4 are used to resist operating conditions at 1200°C, then oxidation resistance and flexural resistance are improved, but fracture toughness is too low (lower than 10 MPa m0.5)
Solution Approach 1:
The patent creates composite materials combining structural ceramics with structural silicides, where the silicide phase provides ductility and fracture toughness while the ceramic phase provides oxidation resistance and flexural strength, achieving a balance of properties suitable for gas turbine applications
3Strength
If MoSi2+Si3N4 composite materials are produced by sintering, then low density and excellent oxidation resistance are achieved, but fracture toughness remains too low for gas turbine applications
Solution Approach 1:
The patent modifies the sintering process by adding specific oxide components (Al2O3, TiO2, HfO2, ZrO2, Ta2O5, Nb2O5, WO3, MoO3, ZnO, CeO2, Y2O3) to the MoSi2-Si3N4 system, where these oxides form grain boundary phases that significantly improve fracture toughness while maintaining the low density and oxidation resistance of the base composite
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 material exhibits significantly improved mechanical, physical, and thermal properties, including high ultimate tensile strength, Young's modulus, and fracture toughness, making it suitable for high-temperature gas turbine components without the need for internal cooling channels.
Implementation Method 1
melting at least a part of the powders by activating a power source, said source having an energy power of 150-1000 W
Data Source
AI summary
A silicide-based composite material is disclosed, comprising a silicide of Mo, B, W, Nb, Ta, Ti, Cr, Co, Y, or a combination thereof, Si3N4, and at least an oxide, as well as and a process for producing the same.