Single Crystal Casting IN713LC Turbine Blades
Introduction
Turbine blades made using single crystal casting represent the highest standard in high-temperature performance and durability. Unlike conventional castings, single crystal blades contain no grain boundaries, significantly improving creep resistance and oxidation stability under extreme stress. IN713LC, a nickel-based superalloy, is well-suited for this process due to its excellent high-temperature strength and phase stability.
Neway AeroTech offers advanced single crystal casting services for IN713LC turbine blades, tailored for use in aerospace, power generation, and defense applications. Our casting process achieves exceptional directional solidification and structural precision for critical hot-section engine components.
Core Technology of IN713LC Single Crystal Turbine Blade Casting
Wax Pattern Production Precision wax patterns are manufactured with tolerances of ±0.05 mm to replicate the blade’s aerodynamic geometry and internal cooling structures.
Shell Building Multiple ceramic slurry and refractory stucco layers are applied to create molds with thermal resistance and dimensional fidelity up to 1200°C.
Directional Grain Selector Design A spiral selector or helical grain starter is incorporated into the mold base to initiate and control single crystal growth during solidification.
Vacuum Melting and Pouring IN713LC alloy is melted at ~1450°C using vacuum induction melting under a vacuum of ≤10⁻³ Pa, reducing oxides and gas inclusions.
Directional Solidification The mold is withdrawn vertically from a high-temperature zone at ~3 mm/min, producing a single crystal structure aligned along the [001] orientation.
Shell Knockout and Cleaning After controlled solidification, the shell is removed via high-pressure blasting, ensuring the preservation of intricate cooling features.
Hot Isostatic Pressing (HIP) Blades are treated under 1150°C and 150 MPa in HIP systems to eliminate micro-voids and enhance mechanical integrity.
Heat Treatment A multistage solution and aging treatment is applied to stabilize the γ' phase, improving creep and fatigue performance.
Material Characteristics of IN713LC for Single Crystal Applications
Although typically used for equiaxed casting, IN713LC can be adapted to single crystal processing for enhanced performance:
Max Operating Temperature: 982°C (1800°F)
Tensile Strength: ≥1034 MPa at room temperature
Yield Strength: ≥862 MPa
Creep Rupture Strength: ≥200 MPa @ 760°C, 1000 hr
Elongation: ≥5%
Phase Stability: γ' volume fraction above 50% with refined carbides and minimal segregation
These properties make IN713LC viable for high-cycle turbine blades operating in harsh environments.
Case Study: IN713LC Single Crystal Blade for Aeroengine HPT Stage
Project Background
A major aeroengine OEM commissioned Neway AeroTech to develop single crystal IN713LC blades for the high-pressure turbine (HPT) stage of a military turbofan. The project emphasized long-term thermal fatigue resistance and dimensional stability under sustained load cycles.
Application Scenarios
Military Turbofan Blades (e.g., F110 engines): Critical for thrust performance and reliability under variable mission conditions.
Power Turbine HPT Blades (e.g., LM2500+): Operate in continuous service near 950°C, demanding long-term creep resistance.
Unmanned Aerial Vehicle Engines: Require lightweight, high-strength turbine blades with high cycle durability.
Gas Generator Turbines (Helicopter Engines): Where thermal gradients and fast startup cycles induce severe fatigue loading.
Blade Structural Features
Airfoil profiles designed for high Mach number flow
Internal serpentine and impingement cooling passages
Root forms: Fir-tree or dovetail compatible with standard disk hubs
Shroud and tip rails for gas sealing under radial growth
Manufacturing Solution for IN713LC Single Crystal Blades
Wax Assembly & Mold Engineering Design integrated with CFD analysis and cooling optimization; wax gating supports proper metal flow and selector alignment.
Vacuum Melting and Directional Casting Using state-of-the-art casting systems, the mold is lowered through a thermal gradient to initiate controlled single crystal growth.
Post-Casting HIP and Heat Treatment HIP eliminates residual porosity; heat treatment enhances γ' phase uniformity, critical for long-term creep life.
CNC Machining & Finishing Critical surfaces and cooling holes are finalized through superalloy CNC machining and EDM for dimensional control.
Quality Control and NDT Each blade is evaluated using X-ray, CMM, and metallographic inspection per AS9100 and NADCAP.
Core Challenges in IN713LC Single Crystal Blade Production
Avoiding stray grain formation during withdrawal
Managing alloy segregation at the root section
Achieving defect-free γ' precipitation post heat-treatment
Machining complex cooling geometries without thermal distortion
Results and Verification
X-ray and CMM verified 100% compliance with geometry and defect criteria
Metallography showed uniform [001] orientation and <2° deviation
Tensile performance exceeded 1034 MPa at 20°C, with superior fatigue behavior
No creep rupture failures after 1000 hours at 760°C under 200 MPa stress
FAQs
Can IN713LC be used for single crystal turbine blade production?
What casting method ensures [001] grain orientation in turbine blades?
What industries benefit most from single crystal IN713LC blades?
What is the difference between equiaxed and single crystal blades?
How is stray grain formation avoided in single crystal casting?
