What Makes an Alloy?
Every alloy begins with a pure metal. Many pure metals, such as iron, copper, and aluminium, have limitations. For instance, they may be too soft, brittle, or reactive. However, some pure metals, like titanium and gold, excel in their natural state. For example, titanium offers exceptional strength and lightweight performance. Similarly, gold provides unmatched conductivity, corrosion resistance, and a variety of uses in electronics, jewellery, and medical devices. These metals, therefore, play crucial roles in specific industries. On the other hand, to broaden applications, pure metals often need enhancements. Consequently, mixing pure metals with other metallic elements creates alloys that are designed to meet specific requirements. Alloys offer several advantages, including:- Improved Strength
- Enhanced Ductility
- Weight Reduction
- Resistance to Environmental Factors
Pure Metals vs. Alloys
Pure metals remain uncombined with other elements and provide unique properties for specific uses. For instance:- Pure Titanium: It is lightweight, corrosion-resistant, and strong. As a result, it is widely used in aerospace, medical implants, and high-performance industrial parts.
- Pure Copper: Due to its superior heat and electrical conductivity, it is essential for wiring, heat exchangers, and electronics.
- Gold and Silver: These metals are highly valued for their conductivity, corrosion resistance, and malleability. For example, gold is commonly used in jewellery, electronics, and medical devices.
- Steel Alloys: These are made from iron and carbon. Moreover, adding chromium produces stainless properties, while nickel improves flexibility.
- Aluminium Alloys: These combine lightweight properties with corrosion resistance, making them ideal for aerospace, transportation, and consumer goods.
- Bronze: As a copper-tin alloy, bronze resists corrosion and works well in marine environments.
- Brass: Copper-zinc alloy, which is malleable and tarnish-resistant, is useful for instruments and fittings.
Types of Alloys
Substitutional Alloys
Substitutional alloys occur when atoms of one metal replace those in the base metal’s crystal structure. For example, in bronze, tin atoms replace some copper atoms, which, in turn, adds strength and anti-corrosion properties.Interstitial Alloys
Interstitial alloys form when smaller atoms fit between base metal atoms. For instance, carbon atoms in carbon steel occupy interstitial spaces, strengthening the metal and increasing its durability.Common Alloy Metals and Their Uses
Steel Alloys
Steel combines iron with carbon and other metals like:- Chromium for stainless steel
- Manganese for strength
- Nickel for corrosion resistance
Aluminium Alloys
Pure aluminium blends with copper, magnesium, or zinc to form aluminium alloys. Consequently, these alloys are lightweight and corrosion-resistant, making them popular in:- Aerospace
- Beverage Cans
- Bike Frames
- Electrical Parts
Cast Iron
Cast iron, rich in carbon, creates durable items like engine blocks, pipes, and cookware. However, it is more brittle than steel.Bronze
Bronze combines copper and tin, offering corrosion resistance. For example, it is used in marine applications, sculptures, and tools.Properties of Alloys
Alloys improve on pure metals by providing the following characteristics:- Strength: For example, steel alloys surpass pure iron in structural applications.
- Corrosion Resistance: Stainless steel, in particular, withstands harsh conditions.
- Hardness: Alloys like bronze and steel provide superior wear resistance.
- Malleability: Brass and aluminium alloys are easier to shape.
- Heat Resistance: Inconel, for instance, performs well in extreme temperatures.
Cold Spray: Pure Metals and Alloys
Cold spray additive manufacturing works with both pure metals and alloys, offering tailored solutions for diverse industries.Applications of Pure Metals
Pure metals in cold spray provide high conductivity, corrosion resistance, and thermal efficiency. For example:- Electrical Coatings: Copper and silver ensure conductivity and reliability.
- Heat Exchangers: Copper enhances thermal performance in heat-exchanging components.
- Pure Metal Parts: Titanium suits aerospace, copper fits conductivity needs, and other metals address unique challenges.
Applications of Alloys
Alloys in cold spray combine strength and flexibility for diverse uses:- Structural Components: Steel alloys provide durability for heavy industries.
- Precision Instruments: Invar36 offers low thermal expansion.
- High-Temperature Parts: Inconel performs exceptionally well in heat-intensive environments.
- Lightweight Parts: Aluminium alloys fit aerospace and automotive needs due to their light weight and corrosion resistance.
Why Cold Spray Additive Manufacturing?
Additive manufacturing lets you build parts layer by layer using digital designs. A more specialised version of this is cold spray additive manufacturing (CSAM). This technique comes with advantages such as:
- Speed
- Mechanical Integrity
- Preservation of Material Properties
CSAM is different from other additive manufacturing processes since it doesn’t require heat to melt materials. Instead, it uses kinetic energy to deposit metal powders at high velocity onto surfaces. This creates parts that are as durable as they are versatile, and you’ll see them used in industries from aerospace to defence to automotive.
The Cold Spray Process: An Overview
CSAM is typically achieved with the help of a supersonic gas jet. The “cold” part in the name refers to the fact that the materials never reach their melting points. Instead, these particles undergo plastic deformation upon colliding with the surface, bonding tightly without ever melting.
This makes it a solid-state additive manufacturing process that both minimises heat-related distortion and retains the inherent properties of the material. Melting and solidification are key parts of more traditional additive manufacturing processes, but this leads to a host of problems, including:
- Thermal Stress
- Distortion
- Microstructure Changes in the Final Product
In contrast, cold spraying results in faster production times and superior mechanical properties in the finished product.
Advantages of Cold Spray Additive Manufacturing
Industry-leading speed
Build high-performance metal parts at 5-6kg per hour, competing directly with commercial, traditional manufacturing methods.
Minimal size constraints
Cold spray can build very large metal parts with minimal limitations, with systems designed for parts 3-9 metres in length or larger.
Near-net shape manufacturing
Build parts to near their final desired shape, saving up to 90% of machining waste and saving time and costs.
Multi-metal, seamless parts
Build single-piece parts seamlessly with multiple metals, from titanium, steel, copper, and much more.
Why Cold Spray Additive Manufacturing?
Cold spray additive manufacturing stands out the most in industries where durability and precision are essential:
Heat-Free Application
Cold spraying doesn’t melt materials, significantly reducing thermal stress and preventing undesirable changes in the material’s microstructure. This preserves the material’s original strength, toughness, and resistance to corrosion.
Enhanced Mechanical Properties
Parts made through cold spray usually have mechanical properties superior to those made with traditional methods, including higher density and improved tensile strength. Unlike traditional methods, cold spray avoids thermal cycling, preserving the material’s structural integrity.
Read more about Titomic’s material capabilities here.
Tailor the Manufacturing Process, Tailor the Part
By manipulating the variables of cold spray, such as metal, gas pressure, and temperature, certain mechanical properties can be achieved based on the part requirements, such as ductility, hardness, and so on. Importantly, these characteristics can be altered within the same part.
For example, a steel ballistics plate could feature a very hard strike face, while the rear portion of the plate could be made more ductile, while also featuring titanium for weight reduction.
Fusion of Dissimilar Metals
Because the process doesn’t melt metals, those with different melting points can be fused together. This allows for leveraging the strengths of multiple metals within a single, seamless part, without joining or welding.
For instance, ballistics panels can combine steel and titanium, or aluminium can be applied to steel to remove and protect against corrosion.
Rapid Deposition and Scalability
Cold spray is a fast and scalable additive manufacturing process. It can be used to build large structures quickly, making it highly adaptable across various applications. For example, large pure titanium parts can be built at speeds of 5–6 kilograms per hour.
Large Scale
Cold spray doesn’t require an inert environment, unlike many melt-based methods. This allows for the production of large-scale parts without size limitations.
Minimal Waste
Because the powder particles are directly deposited onto the surface, there is minimal material waste, making cold spray technology environmentally and economically advantageous.
Compatibility with Diverse Materials
You can use cold spray with a wide range of materials, including:
- Commercially pure titanium and Ti-6Al-4V
- Steel and steel alloys
- Inconel 625 and 718
- Aluminium alloys including 6061 and 7075
- Silver, gold, and other precious metals
- Tantalum and other refractive metals
- Tungsten alloys
- Magnesium alloys
- Invar36
- Certain ceramics
Frequently asked questions
TKF costs significantly less than traditional manufacturing methods for the following reasons:
- It doesn’t need large-scale tooling (such as vacuum moulds) to produce parts. A simpler setup means reduced costs.
- It turns metal powder to part in just hours, by depositing the powder at supersonic speed to rapidly build up parts layer by layer – so there’s no need for casting or forging. Plus, the part you need is the part you make, saving time and materials.
- It keeps material costs down. For example, when we manufactured a 1.2m titanium ring, the ‘as built’ weight was 60kg while the final part weighed 56kg – representing a ‘buy to fly’ ratio of 1.08 with material costs of only A$3,000.
Our compact cold spray systems cost considerably less than traditional repair and resurfacing methods for the following reasons:
- You can resurface and refurbish parts in just minutes.
- Materials often cost less than $300.
- You no longer need to outsource repairs. For example, a shower floor manufacturer quoted $40,000 to ship a damaged resin transfer moulding tool overseas spent just $3,000 repairing it with Titomic’s D523 system – as well as saving months of downtime.
We’ve achieved typical density rates of 90-95% and over 99% when enhanced by post-processing.
If needed, it’s also possible to create less dense, more porous coatings for grip, abrasion, chemical processing and more through process optimisation, powder manipulation, and post-processing parameters.
Generally, you can achieve mechanical properties similar to casting and forging. While some parts may need to be processed with a heat treatment to make them more ductile, we can tailor process variables to meet your specific needs – a clear advantage compared to other methods.
It depends on what parts you need, as well as the mechanical properties the application requires. However, generally parts created with TKF will need some post-processing heat treatment.
Cold spray doesn’t require heat to melt the materials being sprayed. This is different to traditional metal spraying methods like welding or thermal spraying, which use heat to melt the material before it’s applied to a surface.
Instead, a high-pressure gas is used to accelerate tiny metal particles (which are usually less than 50 micrometres in size) to supersonic speeds. This creates heat through kinetic energy, when the particles collide with the surface of the object being sprayed.
Cold spray works by exploiting the kinetic energy of tiny metal particles. Low-to-high pressure gas is used to accelerate the particles (which are usually less than 50 micrometres in size) to supersonic speeds. These are then sprayed onto a surface where they compress and deform to create a cohesive bond.
This results in a strong, dense coating that can be used for a variety of applications – such as repairing damaged parts, improving the surface properties of a material, or creating new, complex shapes.
There are many metals that can be used in our cold spray systems. This includes aluminium, copper, nickel, titanium, stainless steel, Inconel, and more.
Since these all have different characteristics – such as strength, ductility, and resistance to corrosion – the chosen metals will depend on the application, as well as the properties needed for the final product.
Some metals may also be easier or more difficult to cold spray, depending on their melting point, ductility, and other factors.
What makes TKF so beneficial is that it can fuse dissimilar metals together. This means you can leverage the strengths of multiple metals in a single, monocoque part. For instance, you can fuse copper to titanium, nickel to cast iron, and much more.
Cold spray can be used on a variety of surfaces. This includes metals, ceramics, plastics, and composites.
The process is particularly useful for repairing worn or damaged metal parts, as it can restore the surface to its original shape and properties without causing distortion or weakening the material.
Our cold spray systems can also be used to add new features or properties to a surface, such as improved wear resistance, corrosion resistance, or thermal properties.
You can even use it to create new shapes or structures that would be difficult or impossible to achieve with traditional manufacturing methods.
- Aerospace: Repair and restore worn or damaged aircraft parts (such as engine blades, landing gear, and wing components), or add corrosion-resistant coatings to aircraft surfaces.
- Automotive: Repair and restore worn or damaged engine components (such as pistons, cylinder heads, and crankshafts), or add wear-resistant coatings to automotive parts.
- Marine: Repair and restore worn or damaged marine components (such as propellers, shafts, and rudders) or add corrosion-resistant coatings to marine structures.
- Oil & gas: Repair and restore corrosion and wear (such as shafts, bearings, piping, and valves).
- Electronics: Add conductive coatings to electronic components (such as circuit boards and antennas), as well as repair and restore electronic devices.
- Manufacturing: Create new shapes or features on metal parts (such as textured surfaces or complex geometries), or add wear-resistant coatings to industrial components (such as machine tools and moulds).
