What are the commonly used metal 3D printing materials in industry?

1. Stainless steel: the best balance between being resistant to rust and being cheap
Stainless steel is the most advanced material system for 3D printing metals. In 2024, 32% of all metal powder used in the world will be 316L stainless steel powder. Its main benefits are:
Very good at resisting corrosion: The design of the alloy, which has at least 10.5% chromium, makes it impossible to replace in industries like petrochemicals and food processing. A certain maritime platform valve manufacturer makes a 316L stainless steel valve using 3D printing technology. This valve lasts three times longer than standard castings in seawater that is corrosive.
High tolerance for the printing process: The large melt pool properties make it very flexible to changes in laser energy, and it has a success rate of over 98%. A particular automobile parts company utilizes a 12-laser collaborative machine to make 12 kg of stainless steel parts per hour. This is 8 times more efficient than a single-laser machine.
The post-processing solution is well-developed. For example, aging treatment can cause martensitic transformation, which raises the tensile strength of 17-4PH stainless steel from 900MPa to 1300MPa. One mould firm makes injection moulds out of this material, which last 40% longer than regular H13 steel moulds.
2. Titanium alloy: an important material for the aerospace and medical areas
Titanium alloy makes about 45% of the high-end metal 3D printing market. Its technological advances are mostly seen in:
TC4 (Ti-6Al-4V) is used on a large scale: You can make a composite structure of columnar crystals and equiaxed crystals by modifying the laser scanning approach. When combined with hot isostatic pressing treatment, the fatigue life of aviation engine blades can be 120% longer than the forging standard. A certain kind of rocket thrust chamber uses topology optimization to construct regenerative cooling channels. This makes it 35% lighter and 28% cheaper to launch.
Breakthrough in biomedical materials innovation: Because it is very biocompatible, pure titanium grade 2 powder has been used in individualized orthopedic implants. A medical institution made a hip joint prosthesis utilizing electron beam melting (EBM) technology. The prosthesis has a porosity that is controlled between 65% to 75%, which speeds up the formation of bone cells by three times.
Making a new alloy system: Adding 0.5% Nb to TiAl intermetallic compounds has made them stronger at high temperatures, going from 1000 °C to 350 MPa. This makes them a great material for turbine blades in aircraft engines. Using directed energy deposition (DED) technology, a research institution has effectively fixed the leading edge damage on a certain type of engine blade. The repair layer and the substrate have a bonding strength of 420MPa.
3. Aluminium alloy: a material that started the lightweight revolution
Three significant problems are solved by aluminium alloy 3D printing technology:
Technology for controlling hot cracks: The AlSi10Mg alloy has 6% to 12% silicon in it, which makes it develop a eutectic structure. This lowers the number of hot cracks from 35% to less than 5%. A certain new energy vehicle company employs this material to make battery pack brackets. Compared to standard die-casting parts, these brackets are 42% lighter and 18% stiffer.
Creating a system to make rare earth stronger: Adding 0.4% Sc to Al Mg Sc Zr alloy makes it stronger than 500MPa and smaller than 1 μm. A certain aerospace company made a satellite bracket out of this material that stays stable in size between -196 °C and 200 °C.
A major advance in large-scale forming: A certain company made a printing cabin that is 1.5m × 0.8m × 0.6m and uses multi-laser synchronous scanning technology to print the whole A350 aircraft window frame. This cuts the weight by 22% compared to traditional riveting structures and cuts the production time from 6 weeks to 72 hours.
4. High-temperature alloys: protectors of harsh environments
Nickel-based high-temperature alloys make approximately 80% of the market for hot end parts of aircraft engines. Their technological evolution shows two main trends:
Technology for controlling microcracks: We were able to lower the crack rate of Inconel 718 alloy from 15% to less than 0.5% by changing the laser energy density (80–120J/mm ³) and scanning spacing (0.08–0.12mm). A certain gas turbine company makes turbine discs utilizing this technology. These discs can last for 1000 hours at 650 °C and 350 MPa.
Gradient material printing: A certain research institution developed functional gradient material (FGM) technology that makes the combustion chamber wall go from a NiCoCrAlY coating to an Inconel 625 substrate in a smooth way. This makes the material three times more resistant to oxidation and gives it a thermal cycle life of more than 5000 times.