For highly regulated industries such as aerospace manufacturing, where components must withstand harsh conditions, thorough quality assurance testing in aerospace is essential. In this context, Dr. Jan Kretschmer, Senior Sales Manager at Thermo Fisher Scientific, explores how combining a range of microscopy techniques is crucial to improving the quality and reliability of aerospace components.
In addition to verifying the production processes of parts, quality assurance testing ensures that materials used within aerospace applications are reliable and meet the required standards, such as AS 9100. Aerospace manufacturers must have a thorough understanding of the microstructural composition of materials used in the product development process, enabling them to prevent issues before they occur.
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Key Materials in Aerospace Manufacturing for Quality Assurance
Some of the most important materials for quality assurance testing engineers to characterise are aluminium and nickel-based superalloys, which play a significant role in aerospace manufacturing.
Aluminium for Aerospace Applications
The aerospace industry increasingly demands materials with enhanced strength, toughness, and corrosion resistance. Aluminium is an ideal choice due to its high strength-to-weight ratio, which helps boost fuel efficiency and provides robust, lightweight components. Additionally, aluminium’s natural corrosion resistance prolongs the working life of components exposed to harsh environments encountered at high altitudes.
Nickel-Based Superalloys: Strength for High-Temperature Aerospace Components
On the other hand, nickel-based superalloys are essential for aerospace components like aircraft engines due to their excellent mechanical properties at high temperatures, as well as their resistance to corrosion, creep, and oxidation. These alloys are vital for ensuring that aerospace components withstand extreme conditions.
The Impact of Manufacturing Processes on Component Quality
While materials like aluminium and nickel-based superalloys provide the necessary mechanical properties, the manufacturing process steps they undergo can have significant effects on their performance. Harsh temperatures and conditions encountered during production may negatively impact their mechanical properties. As a result, applying a range of advanced imaging techniques is essential to ensure that manufacturing processes do not jeopardise safety and quality.
Advanced Microscopy for Quality Assurance Testing in Aerospace
The application of multiple microscopy techniques helps ensure that aerospace components meet high standards. Some of the most important techniques include scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDS). These techniques help engineers identify key details such as grain size, intermetallic particle composition, and dislocation density, which ultimately contribute to the mechanical strength of aerospace components.
Aluminium Lightweighting: Ensuring Quality in Aerospace Manufacturing
A common strategy in aerospace manufacturing to reduce weight across an aircraft’s wings, fuselage, and engine casings is implementing aluminium-lithium (Al-Li) stiffened panels. To avoid hot cracking, friction stir welding (FSW) is preferred. This process results in a lower processing temperature and prevents safety issues such as cracks or porosity.
However, the weld region often ends up softer and with reduced yield strength compared to the base material. Quality assurance testing is essential to investigate the nanoscale changes that occur in the stirred zone. By employing techniques such as SEM and EBSD, engineers can analyse the grain structure and composition of the alloy to understand how these changes impact mechanical properties.
The Importance of Alloying Elements in Aerospace Materials
Another critical area of quality assurance testing is analysing the effect of adding alloying elements to materials such as AA2024, a widely used aluminium alloy. The addition of elements like copper, magnesium, or manganese results in the formation of precipitates that vary based on applied treatments. For effective quality assurance testing, aerospace engineers need to characterize these elements thoroughly, revealing how different treatments like aging, hardening, or annealing affect alloy properties.
By using tools like the Thermo Scientific Apreo ChemiSEM, engineers can combine SEM, EDS, and EBSD techniques in a single microscope to get a comprehensive view of alloy composition, grain structure, and precipitate formation. These insights are invaluable for refining aluminium alloys to meet the stringent standards of aerospace manufacturing.
Extreme Temperatures and the Role of Quality Assurance Testing
In the case of nickel-based superalloys, which are used in aerospace components such as engines that endure temperatures of up to 2,000°C, quality assurance testing ensures that the alloys can withstand such harsh conditions. The Apreo ChemiSEM provides high-resolution SEM imaging to visualise the material’s internal structures and surface, while EDS maps the distribution of elements like nickel, chromium, and aluminium in superalloys.
Moreover, particle analysis allows engineers to quantify and categorise particles like carbides and oxides, which significantly affect properties such as creep resistance and corrosion. By understanding the characteristics of these particles, aerospace manufacturing companies can refine material treatments to optimize the durability and performance of critical components.
Quality Assurance Testing for Thermal Barrier Coatings (TBCs)
Thermal barrier coatings (TBCs) are essential for protecting aerospace components used in high-temperature applications. By integrating the Apreo ChemiSEM with the CleanMill Broad Ion Beam (BIB) System, engineers can observe phase transformations and elemental distributions within TBC layers. This process is crucial for optimizing TBC formulations to extend the lifespan of components exposed to high temperatures and oxidation.
The quality assurance testing approach, which combines advanced imaging with AI-assisted analysis using Thermo Scientific™ Avizo™ 3D Pro Software, offers a comprehensive characterization of TBCs. This analysis reveals how elements like magnesium and zirconium behave under thermal cycling, providing valuable insights for improving the durability of aerospace components.
Conclusion: Ensuring Safety and Performance with Quality Assurance Testing in Aerospace
In the highly regulated aerospace industry, quality assurance testing in aerospace manufacturing is essential to ensure the safety, reliability, and performance of components. By combining a wide range of microscopy and imaging techniques, aerospace engineers can fully understand the microstructural properties of materials like aluminium and nickel-based superalloys, ensuring they meet rigorous industry standards. These comprehensive tests play a pivotal role in improving the quality and durability of components used in high-demand aerospace applications. For more information visit Thermo Fischer
